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Commit Graph

11348 Commits

Author SHA1 Message Date
Naoya Horiguchi
4b0ece6fa0 mm: migrate: fix remove_migration_pte() for ksm pages
I found that calling page migration for ksm pages causes the following
bug:

    page:ffffea0004d51180 count:2 mapcount:2 mapping:ffff88013c785141 index:0x913
    flags: 0x57ffffc0040068(uptodate|lru|active|swapbacked)
    raw: 0057ffffc0040068 ffff88013c785141 0000000000000913 0000000200000001
    raw: ffffea0004d5f9e0 ffffea0004d53f60 0000000000000000 ffff88007d81b800
    page dumped because: VM_BUG_ON_PAGE(!PageLocked(page))
    page->mem_cgroup:ffff88007d81b800
    ------------[ cut here ]------------
    kernel BUG at /src/linux-dev/mm/rmap.c:1086!
    invalid opcode: 0000 [#1] SMP
    Modules linked in: ppdev parport_pc virtio_balloon i2c_piix4 pcspkr parport i2c_core acpi_cpufreq ip_tables xfs libcrc32c ata_generic pata_acpi ata_piix 8139too libata virtio_blk 8139cp crc32c_intel mii virtio_pci virtio_ring serio_raw virtio floppy dm_mirror dm_region_hash dm_log dm_mod
    CPU: 0 PID: 3162 Comm: bash Not tainted 4.11.0-rc2-mm1+ #1
    Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
    RIP: 0010:do_page_add_anon_rmap+0x1ba/0x260
    RSP: 0018:ffffc90002473b30 EFLAGS: 00010282
    RAX: 0000000000000021 RBX: ffffea0004d51180 RCX: 0000000000000006
    RDX: 0000000000000000 RSI: 0000000000000082 RDI: ffff88007dc0dfe0
    RBP: ffffc90002473b58 R08: 00000000fffffffe R09: 00000000000001c1
    R10: 0000000000000005 R11: 00000000000001c0 R12: ffff880139ab3d80
    R13: 0000000000000000 R14: 0000700000000200 R15: 0000160000000000
    FS:  00007f5195f50740(0000) GS:ffff88007dc00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00007fd450287000 CR3: 000000007a08e000 CR4: 00000000001406f0
    Call Trace:
     page_add_anon_rmap+0x18/0x20
     remove_migration_pte+0x220/0x2c0
     rmap_walk_ksm+0x143/0x220
     rmap_walk+0x55/0x60
     remove_migration_ptes+0x53/0x80
     migrate_pages+0x8ed/0xb60
     soft_offline_page+0x309/0x8d0
     store_soft_offline_page+0xaf/0xf0
     dev_attr_store+0x18/0x30
     sysfs_kf_write+0x3a/0x50
     kernfs_fop_write+0xff/0x180
     __vfs_write+0x37/0x160
     vfs_write+0xb2/0x1b0
     SyS_write+0x55/0xc0
     do_syscall_64+0x67/0x180
     entry_SYSCALL64_slow_path+0x25/0x25
    RIP: 0033:0x7f51956339e0
    RSP: 002b:00007ffcfa0dffc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
    RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007f51956339e0
    RDX: 000000000000000c RSI: 00007f5195f53000 RDI: 0000000000000001
    RBP: 00007f5195f53000 R08: 000000000000000a R09: 00007f5195f50740
    R10: 000000000000000b R11: 0000000000000246 R12: 00007f5195907400
    R13: 000000000000000c R14: 0000000000000001 R15: 0000000000000000
    Code: fe ff ff 48 81 c2 00 02 00 00 48 89 55 d8 e8 2e c3 fd ff 48 8b 55 d8 e9 42 ff ff ff 48 c7 c6 e0 52 a1 81 48 89 df e8 46 ad fe ff <0f> 0b 48 83 e8 01 e9 7f fe ff ff 48 83 e8 01 e9 96 fe ff ff 48
    RIP: do_page_add_anon_rmap+0x1ba/0x260 RSP: ffffc90002473b30
    ---[ end trace a679d00f4af2df48 ]---
    Kernel panic - not syncing: Fatal exception
    Kernel Offset: disabled
    ---[ end Kernel panic - not syncing: Fatal exception

The problem is in the following lines:

    new = page - pvmw.page->index +
        linear_page_index(vma, pvmw.address);

The 'new' is calculated with 'page' which is given by the caller as a
destination page and some offset adjustment for thp.  But this doesn't
properly work for ksm pages because pvmw.page->index doesn't change for
each address but linear_page_index() changes, which means that 'new'
points to different pages for each addresses backed by the ksm page.  As
a result, we try to set totally unrelated pages as destination pages,
and that causes kernel crash.

This patch fixes the miscalculation and makes ksm page migration work
fine.

Fixes: 3fe87967c5 ("mm: convert remove_migration_pte() to use page_vma_mapped_walk()")
Link: http://lkml.kernel.org/r/1489717683-29905-1-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-31 17:13:30 -07:00
Al Viro
db68ce10c4 new helper: uaccess_kernel()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-28 16:43:25 -04:00
Peter Zijlstra
8ce371f984 lockdep: Fix per-cpu static objects
Since commit 383776fa75 ("locking/lockdep: Handle statically initialized
PER_CPU locks properly") we try to collapse per-cpu locks into a single
class by giving them all the same key. For this key we choose the canonical
address of the per-cpu object, which would be the offset into the per-cpu
area.

This has two problems:

 - there is a case where we run !0 lock->key through static_obj() and
   expect this to pass; it doesn't for canonical pointers.

 - 0 is a valid canonical address.

Cure both issues by redefining the canonical address as the address of the
per-cpu variable on the boot CPU.

Since I didn't want to rely on CPU0 being the boot-cpu, or even existing at
all, track the boot CPU in a variable.

Fixes: 383776fa75 ("locking/lockdep: Handle statically initialized PER_CPU locks properly")
Reported-by: kernel test robot <fengguang.wu@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-mm@kvack.org
Cc: wfg@linux.intel.com
Cc: kernel test robot <fengguang.wu@intel.com>
Cc: LKP <lkp@01.org>
Link: http://lkml.kernel.org/r/20170320114108.kbvcsuepem45j5cr@hirez.programming.kicks-ass.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-26 15:09:45 +02:00
Jan Kara
b1c51afc00 bdi: Rename cgwb_bdi_destroy() to cgwb_bdi_unregister()
Rename cgwb_bdi_destroy() to cgwb_bdi_unregister() as it gets called
from bdi_unregister() which is not necessarily called from bdi_destroy()
and thus the name is somewhat misleading.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-22 20:11:31 -06:00
Jan Kara
4514451e79 bdi: Do not wait for cgwbs release in bdi_unregister()
Currently we wait for all cgwbs to get released in cgwb_bdi_destroy()
(called from bdi_unregister()). That is however unnecessary now when
cgwb->bdi is a proper refcounted reference (thus bdi cannot get
released before all cgwbs are released) and when cgwb_bdi_destroy()
shuts down writeback directly.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-22 20:11:30 -06:00
Jan Kara
5318ce7d46 bdi: Shutdown writeback on all cgwbs in cgwb_bdi_destroy()
Currently we waited for all cgwbs to get freed in cgwb_bdi_destroy()
which also means that writeback has been shutdown on them. Since this
wait is going away, directly shutdown writeback on cgwbs from
cgwb_bdi_destroy() to avoid live writeback structures after
bdi_unregister() has finished. To make that safe with concurrent
shutdown from cgwb_release_workfn(), we also have to make sure
wb_shutdown() returns only after the bdi_writeback structure is really
shutdown.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-22 20:11:28 -06:00
Jan Kara
e8cb72b322 bdi: Unify bdi->wb_list handling for root wb_writeback
Currently root wb_writeback structure is added to bdi->wb_list in
bdi_init() and never removed. That is different from all other
wb_writeback structures which get added to the list when created and
removed from it before wb_shutdown().

So move list addition of root bdi_writeback to bdi_register() and list
removal of all wb_writeback structures to wb_shutdown(). That way a
wb_writeback structure is on bdi->wb_list if and only if it can handle
writeback and it will make it easier for us to handle shutdown of all
wb_writeback structures in bdi_unregister().

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-22 20:11:27 -06:00
Jan Kara
810df54a64 bdi: Make wb->bdi a proper reference
Make wb->bdi a proper refcounted reference to bdi for all bdi_writeback
structures except for the one embedded inside struct backing_dev_info.
That will allow us to simplify bdi unregistration.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-22 20:11:25 -06:00
Jan Kara
b7d680d7bf bdi: Mark congested->bdi as internal
congested->bdi pointer is used only to be able to remove congested
structure from bdi->cgwb_congested_tree on structure release. Moreover
the pointer can become NULL when we unregister the bdi. Rename the field
to __bdi and add a comment to make it more explicit this is internal
stuff of memcg writeback code and people should not use the field as
such use will be likely race prone.

We do not bother with converting congested->bdi to a proper refcounted
reference. It will be slightly ugly to special-case bdi->wb.congested to
avoid effectively a cyclic reference of bdi to itself and the reference
gets cleared from bdi_unregister() making it impossible to reference
a freed bdi.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-22 20:11:24 -06:00
Huang Ying
093b995e3b mm, swap: Remove WARN_ON_ONCE() in free_swap_slot()
Before commit 452b94b8c8 ("mm/swap: don't BUG_ON() due to
uninitialized swap slot cache"), the following bug is reported,

  ------------[ cut here ]------------
  kernel BUG at mm/swap_slots.c:270!
  invalid opcode: 0000 [#1] SMP
  CPU: 5 PID: 1745 Comm: (sd-pam) Not tainted 4.11.0-rc1-00243-g24c534bb161b #1
  Hardware name: System manufacturer System Product Name/Z170-K, BIOS 1803 05/06/2016
  RIP: 0010:free_swap_slot+0xba/0xd0
  Call Trace:
   swap_free+0x36/0x40
   do_swap_page+0x360/0x6d0
   __handle_mm_fault+0x880/0x1080
   handle_mm_fault+0xd0/0x240
   __do_page_fault+0x232/0x4d0
   do_page_fault+0x20/0x70
   page_fault+0x22/0x30
  ---[ end trace aefc9ede53e0ab21 ]---

This is raised by the BUG_ON(!swap_slot_cache_initialized) in
free_swap_slot().  This is incorrect, because even if the swap slots
cache fails to be initialized, the swap should operate properly without
the swap slots cache.  And the use_swap_slot_cache check later in the
function will protect the uninitialized swap slots cache case.

In commit 452b94b8c8, the BUG_ON() is replaced by WARN_ON_ONCE().  In
the patch, the WARN_ON_ONCE() is removed too.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-21 14:13:19 -07:00
Linus Torvalds
452b94b8c8 mm/swap: don't BUG_ON() due to uninitialized swap slot cache
This BUG_ON() triggered for me once at shutdown, and I don't see a
reason for the check.  The code correctly checks whether the swap slot
cache is usable or not, so an uninitialized swap slot cache is not
actually problematic afaik.

I've temporarily just switched the BUG_ON() to a WARN_ON_ONCE(), since
I'm not sure why that seemingly pointless check was there.  I suspect
the real fix is to just remove it entirely, but for now we'll warn about
it but not bring the machine down.

Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-19 19:00:47 -07:00
Kirill A. Shutemov
2947ba054a x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation
This patch provides all required callbacks required by the generic
get_user_pages_fast() code and switches x86 over - and removes
the platform specific implementation.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K . V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170316213906.89528-1-kirill.shutemov@linux.intel.com
[ Minor readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-18 09:48:03 +01:00
Kirill A. Shutemov
73e10a6181 mm/gup: Provide callback to check if __GUP_fast() is allowed for the range
This is a preparation patch for the transition of x86 to the generic GUP_fast()
implementation.

On x86, get_user_pages_fast() does a couple of sanity checks to see if we can
call __get_user_pages_fast() for the range.

This kind of wrapping protection should be useful for the generic code too.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K . V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170316152655.37789-7-kirill.shutemov@linux.intel.com
[ Small readability edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-18 09:48:03 +01:00
Kirill A. Shutemov
b59f65fa07 mm/gup: Implement the dev_pagemap() logic in the generic get_user_pages_fast() function
This is a preparation patch for the transition of x86 to the generic GUP_fast()
implementation.

Prepare generic GUP_fast() to handle dev_pagemap(). At the moment, it's
only implemented on x86. On non-x86, the new code will be compiled out.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K . V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170316152655.37789-6-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-18 09:48:02 +01:00
Kirill A. Shutemov
e93480537f mm/gup: Mark all pages PageReferenced in generic get_user_pages_fast()
This is a preparation patch for the transition of x86 to the generic GUP_fast()
implementation.

Unlike generic GUP_fast(), the x86 version makes all pages it touches
referenced. It seems required for GRU and EPT.

See the following commit:

  8ee53820ed ("thp: mmu_notifier_test_young")

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K . V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170316152655.37789-5-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-18 09:48:02 +01:00
Kirill A. Shutemov
0005d20b2f mm/gup: Move page table entry dereference into helper function
This is a preparation patch for the transition of x86 to the generic GUP_fast()
implementation.

On x86 PAE, page table entry is larger than sizeof(long) and we would
need to provide a helper that can read the entry atomically.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K . V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170316152655.37789-4-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-18 09:48:02 +01:00
Kirill A. Shutemov
e7884f8ead mm/gup: Move permission checks into helpers
This is a preparation patch for the transition of x86 to the generic GUP_fast()
implementation.

On x86, we would need to do additional permission checks to determine if
access is allowed.

Let's abstract it out into separate helpers.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K . V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170316152655.37789-3-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-18 09:48:01 +01:00
Kirill A. Shutemov
9a804fecee mm/gup: Drop the arch_pte_access_permitted() MMU callback
The only arch that defines it to something meaningful is x86.
But x86 doesn't use the generic GUP_fast() implementation -- the
only place where the callback is called.

Let's drop it.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aneesh Kumar K . V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170316152655.37789-2-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-18 09:48:01 +01:00
Thomas Garnier
f991376e44 x86/mm: Correct fixmap header usage on adaptable MODULES_END
This patch removes fixmap header usage on non-x86 code that was
introduced by the adaptable MODULE_END change.

Signed-off-by: Thomas Garnier <thgarnie@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170317175034.4701-1-thgarnie@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-18 09:48:00 +01:00
Ingo Molnar
74c8ce958d Merge branch 'linus' into x86/mm, to pick up a bugfix
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-17 08:55:01 +01:00
Heiko Carstens
55adc1d05d mm: add private lock to serialize memory hotplug operations
Commit bfc8c90139 ("mem-hotplug: implement get/put_online_mems")
introduced new functions get/put_online_mems() and mem_hotplug_begin/end()
in order to allow similar semantics for memory hotplug like for cpu
hotplug.

The corresponding functions for cpu hotplug are get/put_online_cpus()
and cpu_hotplug_begin/done() for cpu hotplug.

The commit however missed to introduce functions that would serialize
memory hotplug operations like they are done for cpu hotplug with
cpu_maps_update_begin/done().

This basically leaves mem_hotplug.active_writer unprotected and allows
concurrent writers to modify it, which may lead to problems as outlined
by commit f931ab479d ("mm: fix devm_memremap_pages crash, use
mem_hotplug_{begin, done}").

That commit was extended again with commit b5d24fda9c ("mm,
devm_memremap_pages: hold device_hotplug lock over mem_hotplug_{begin,
done}") which serializes memory hotplug operations for some call sites
by using the device_hotplug lock.

In addition with commit 3fc2192410 ("mm: validate device_hotplug is held
for memory hotplug") a sanity check was added to mem_hotplug_begin() to
verify that the device_hotplug lock is held.

This in turn triggers the following warning on s390:

WARNING: CPU: 6 PID: 1 at drivers/base/core.c:643 assert_held_device_hotplug+0x4a/0x58
 Call Trace:
  assert_held_device_hotplug+0x40/0x58)
  mem_hotplug_begin+0x34/0xc8
  add_memory_resource+0x7e/0x1f8
  add_memory+0xda/0x130
  add_memory_merged+0x15c/0x178
  sclp_detect_standby_memory+0x2ae/0x2f8
  do_one_initcall+0xa2/0x150
  kernel_init_freeable+0x228/0x2d8
  kernel_init+0x2a/0x140
  kernel_thread_starter+0x6/0xc

One possible fix would be to add more lock_device_hotplug() and
unlock_device_hotplug() calls around each call site of
mem_hotplug_begin/end().  But that would give the device_hotplug lock
additional semantics it better should not have (serialize memory hotplug
operations).

Instead add a new memory_add_remove_lock which has the similar semantics
like cpu_add_remove_lock for cpu hotplug.

To keep things hopefully a bit easier the lock will be locked and unlocked
within the mem_hotplug_begin/end() functions.

Link: http://lkml.kernel.org/r/20170314125226.16779-2-heiko.carstens@de.ibm.com
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-16 16:56:18 -07:00
Dmitry Vyukov
171012f561 mm: don't warn when vmalloc() fails due to a fatal signal
When vmalloc() fails it prints a very lengthy message with all the
details about memory consumption assuming that it happened due to OOM.

However, vmalloc() can also fail due to fatal signal pending.  In such
case the message is quite confusing because it suggests that it is OOM
but the numbers suggest otherwise.  The messages can also pollute
console considerably.

Don't warn when vmalloc() fails due to fatal signal pending.

Link: http://lkml.kernel.org/r/20170313114425.72724-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-16 16:56:18 -07:00
Vitaly Wool
271df90e4e z3fold: fix spinlock unlocking in page reclaim
Commmit 5a27aa8220 ("z3fold: add kref refcounting") introduced a bug
in z3fold_reclaim_page() with function exit that may leave pool->lock
spinlock held.  Here comes the trivial fix.

Fixes: 5a27aa8220 ("z3fold: add kref refcounting")
Link: http://lkml.kernel.org/r/20170311222239.7b83d8e7ef1914e05497649f@gmail.com
Reported-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-16 16:56:18 -07:00
Thomas Gleixner
383776fa75 locking/lockdep: Handle statically initialized PER_CPU locks properly
If a PER_CPU struct which contains a spin_lock is statically initialized
via:

DEFINE_PER_CPU(struct foo, bla) = {
	.lock = __SPIN_LOCK_UNLOCKED(bla.lock)
};

then lockdep assigns a seperate key to each lock because the logic for
assigning a key to statically initialized locks is to use the address as
the key. With per CPU locks the address is obvioulsy different on each CPU.

That's wrong, because all locks should have the same key.

To solve this the following modifications are required:

 1) Extend the is_kernel/module_percpu_addr() functions to hand back the
    canonical address of the per CPU address, i.e. the per CPU address
    minus the per CPU offset.

 2) Check the lock address with these functions and if the per CPU check
    matches use the returned canonical address as the lock key, so all per
    CPU locks have the same key.

 3) Move the static_obj(key) check into look_up_lock_class() so this check
    can be avoided for statically initialized per CPU locks.  That's
    required because the canonical address fails the static_obj(key) check
    for obvious reasons.

Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ Merged Dan's fixups for !MODULES and !SMP into this patch. ]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170227143736.pectaimkjkan5kow@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-16 09:57:08 +01:00
Thomas Garnier
f06bdd4001 x86/mm: Adapt MODULES_END based on fixmap section size
This patch aligns MODULES_END to the beginning of the fixmap section.
It optimizes the space available for both sections. The address is
pre-computed based on the number of pages required by the fixmap
section.

It will allow GDT remapping in the fixmap section. The current
MODULES_END static address does not provide enough space for the kernel
to support a large number of processors.

Signed-off-by: Thomas Garnier <thgarnie@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Luis R . Rodriguez <mcgrof@kernel.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rafael J . Wysocki <rjw@rjwysocki.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: kasan-dev@googlegroups.com
Cc: kernel-hardening@lists.openwall.com
Cc: kvm@vger.kernel.org
Cc: lguest@lists.ozlabs.org
Cc: linux-doc@vger.kernel.org
Cc: linux-efi@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-pm@vger.kernel.org
Cc: xen-devel@lists.xenproject.org
Cc: zijun_hu <zijun_hu@htc.com>
Link: http://lkml.kernel.org/r/20170314170508.100882-1-thgarnie@google.com
[ Small build fix. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-16 09:06:24 +01:00
Linus Torvalds
83e6322675 Merge branch 'for-4.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
Pull percpu fixes from Tejun Heo:

 - the allocation path was updating pcpu_nr_empty_pop_pages without the
   required locking which can lead to incorrect handling of empty chunks
   (e.g. keeping too many around), which is buggy but shouldn't lead to
   critical failures. Fixed by adding the locking

 - a trivial patch to drop an unused param from pcpu_get_pages()

* 'for-4.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
  percpu: remove unused chunk_alloc parameter from pcpu_get_pages()
  percpu: acquire pcpu_lock when updating pcpu_nr_empty_pop_pages
2017-03-14 14:48:50 -07:00
Kirill A. Shutemov
ce70df0891 mm, gup: fix typo in gup_p4d_range()
gup_p4d_range() should call gup_pud_range(), not itself.

[ This was not noticed on x86: this is the HAVE_GENERIC_RCU_GUP code
  used by arm[64] and powerpc    - Linus ]

Fixes: c2febafc67 ("mm: convert generic code to 5-level paging")
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reported-by: Anton Blanchard <anton@samba.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-13 08:58:09 -07:00
Linus Torvalds
baeedc7158 Merge branch 'prep-for-5level'
Merge 5-level page table prep from Kirill Shutemov:
 "Here's relatively low-risk part of 5-level paging patchset. Merging it
  now will make x86 5-level paging enabling in v4.12 easier.

  The first patch is actually x86-specific: detect 5-level paging
  support. It boils down to single define.

  The rest of patchset converts Linux MMU abstraction from 4- to 5-level
  paging.

  Enabling of new abstraction in most cases requires adding single line
  of code in arch-specific code. The rest is taken care by asm-generic/.

  Changes to mm/ code are mostly mechanical: add support for new page
  table level -- p4d_t -- where we deal with pud_t now.

  v2:
   - fix build on microblaze (Michal);
   - comment for __ARCH_HAS_5LEVEL_HACK in kasan_populate_zero_shadow();
   - acks from Michal"

* emailed patches from Kirill A Shutemov <kirill.shutemov@linux.intel.com>:
  mm: introduce __p4d_alloc()
  mm: convert generic code to 5-level paging
  asm-generic: introduce <asm-generic/pgtable-nop4d.h>
  arch, mm: convert all architectures to use 5level-fixup.h
  asm-generic: introduce __ARCH_USE_5LEVEL_HACK
  asm-generic: introduce 5level-fixup.h
  x86/cpufeature: Add 5-level paging detection
2017-03-10 08:59:07 -08:00
Linus Torvalds
8fe3ccaed0 Merge branch 'akpm' (patches from Andrew)
Merge fixes from Andrew Morton:
 "26 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (26 commits)
  userfaultfd: remove wrong comment from userfaultfd_ctx_get()
  fat: fix using uninitialized fields of fat_inode/fsinfo_inode
  sh: cayman: IDE support fix
  kasan: fix races in quarantine_remove_cache()
  kasan: resched in quarantine_remove_cache()
  mm: do not call mem_cgroup_free() from within mem_cgroup_alloc()
  thp: fix another corner case of munlock() vs. THPs
  rmap: fix NULL-pointer dereference on THP munlocking
  mm/memblock.c: fix memblock_next_valid_pfn()
  userfaultfd: selftest: vm: allow to build in vm/ directory
  userfaultfd: non-cooperative: userfaultfd_remove revalidate vma in MADV_DONTNEED
  userfaultfd: non-cooperative: fix fork fctx->new memleak
  mm/cgroup: avoid panic when init with low memory
  drivers/md/bcache/util.h: remove duplicate inclusion of blkdev.h
  mm/vmstats: add thp_split_pud event for clarity
  include/linux/fs.h: fix unsigned enum warning with gcc-4.2
  userfaultfd: non-cooperative: release all ctx in dup_userfaultfd_complete
  userfaultfd: non-cooperative: robustness check
  userfaultfd: non-cooperative: rollback userfaultfd_exit
  x86, mm: unify exit paths in gup_pte_range()
  ...
2017-03-10 08:34:42 -08:00
Dmitry Vyukov
ce5bec54bb kasan: fix races in quarantine_remove_cache()
quarantine_remove_cache() frees all pending objects that belong to the
cache, before we destroy the cache itself.  However there are currently
two possibilities how it can fail to do so.

First, another thread can hold some of the objects from the cache in
temp list in quarantine_put().  quarantine_put() has a windows of
enabled interrupts, and on_each_cpu() in quarantine_remove_cache() can
finish right in that window.  These objects will be later freed into the
destroyed cache.

Then, quarantine_reduce() has the same problem.  It grabs a batch of
objects from the global quarantine, then unlocks quarantine_lock and
then frees the batch.  quarantine_remove_cache() can finish while some
objects from the cache are still in the local to_free list in
quarantine_reduce().

Fix the race with quarantine_put() by disabling interrupts for the whole
duration of quarantine_put().  In combination with on_each_cpu() in
quarantine_remove_cache() it ensures that quarantine_remove_cache()
either sees the objects in the per-cpu list or in the global list.

Fix the race with quarantine_reduce() by protecting quarantine_reduce()
with srcu critical section and then doing synchronize_srcu() at the end
of quarantine_remove_cache().

I've done some assessment of how good synchronize_srcu() works in this
case.  And on a 4 CPU VM I see that it blocks waiting for pending read
critical sections in about 2-3% of cases.  Which looks good to me.

I suspect that these races are the root cause of some GPFs that I
episodically hit.  Previously I did not have any explanation for them.

  BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8
  IP: qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155
  PGD 6aeea067
  PUD 60ed7067
  PMD 0
  Oops: 0000 [#1] SMP KASAN
  Dumping ftrace buffer:
     (ftrace buffer empty)
  Modules linked in:
  CPU: 0 PID: 13667 Comm: syz-executor2 Not tainted 4.10.0+ #60
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  task: ffff88005f948040 task.stack: ffff880069818000
  RIP: 0010:qlist_free_all+0x2e/0xc0 mm/kasan/quarantine.c:155
  RSP: 0018:ffff88006981f298 EFLAGS: 00010246
  RAX: ffffea0000ffff00 RBX: 0000000000000000 RCX: ffffea0000ffff1f
  RDX: 0000000000000000 RSI: ffff88003fffc3e0 RDI: 0000000000000000
  RBP: ffff88006981f2c0 R08: ffff88002fed7bd8 R09: 00000001001f000d
  R10: 00000000001f000d R11: ffff88006981f000 R12: ffff88003fffc3e0
  R13: ffff88006981f2d0 R14: ffffffff81877fae R15: 0000000080000000
  FS:  00007fb911a2d700(0000) GS:ffff88003ec00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00000000000000c8 CR3: 0000000060ed6000 CR4: 00000000000006f0
  Call Trace:
   quarantine_reduce+0x10e/0x120 mm/kasan/quarantine.c:239
   kasan_kmalloc+0xca/0xe0 mm/kasan/kasan.c:590
   kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:544
   slab_post_alloc_hook mm/slab.h:456 [inline]
   slab_alloc_node mm/slub.c:2718 [inline]
   kmem_cache_alloc_node+0x1d3/0x280 mm/slub.c:2754
   __alloc_skb+0x10f/0x770 net/core/skbuff.c:219
   alloc_skb include/linux/skbuff.h:932 [inline]
   _sctp_make_chunk+0x3b/0x260 net/sctp/sm_make_chunk.c:1388
   sctp_make_data net/sctp/sm_make_chunk.c:1420 [inline]
   sctp_make_datafrag_empty+0x208/0x360 net/sctp/sm_make_chunk.c:746
   sctp_datamsg_from_user+0x7e8/0x11d0 net/sctp/chunk.c:266
   sctp_sendmsg+0x2611/0x3970 net/sctp/socket.c:1962
   inet_sendmsg+0x164/0x5b0 net/ipv4/af_inet.c:761
   sock_sendmsg_nosec net/socket.c:633 [inline]
   sock_sendmsg+0xca/0x110 net/socket.c:643
   SYSC_sendto+0x660/0x810 net/socket.c:1685
   SyS_sendto+0x40/0x50 net/socket.c:1653

I am not sure about backporting.  The bug is quite hard to trigger, I've
seen it few times during our massive continuous testing (however, it
could be cause of some other episodic stray crashes as it leads to
memory corruption...).  If it is triggered, the consequences are very
bad -- almost definite bad memory corruption.  The fix is non trivial
and has chances of introducing new bugs.  I am also not sure how
actively people use KASAN on older releases.

[dvyukov@google.com: - sorted includes[
  Link: http://lkml.kernel.org/r/20170309094028.51088-1-dvyukov@google.com
Link: http://lkml.kernel.org/r/20170308151532.5070-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 17:01:10 -08:00
Dmitry Vyukov
68fd814a33 kasan: resched in quarantine_remove_cache()
We see reported stalls/lockups in quarantine_remove_cache() on machines
with large amounts of RAM.  quarantine_remove_cache() needs to scan
whole quarantine in order to take out all objects belonging to the
cache.  Quarantine is currently 1/32-th of RAM, e.g.  on a machine with
256GB of memory that will be 8GB.  Moreover quarantine scanning is a
walk over uncached linked list, which is slow.

Add cond_resched() after scanning of each non-empty batch of objects.
Batches are specifically kept of reasonable size for quarantine_put().
On a machine with 256GB of RAM we should have ~512 non-empty batches,
each with 16MB of objects.

Link: http://lkml.kernel.org/r/20170308154239.25440-1-dvyukov@google.com
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 17:01:10 -08:00
Tahsin Erdogan
40e952f9d6 mm: do not call mem_cgroup_free() from within mem_cgroup_alloc()
mem_cgroup_free() indirectly calls wb_domain_exit() which is not
prepared to deal with a struct wb_domain object that hasn't executed
wb_domain_init().  For instance, the following warning message is
printed by lockdep if alloc_percpu() fails in mem_cgroup_alloc():

  INFO: trying to register non-static key.
  the code is fine but needs lockdep annotation.
  turning off the locking correctness validator.
  CPU: 1 PID: 1950 Comm: mkdir Not tainted 4.10.0+ #151
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  Call Trace:
   dump_stack+0x67/0x99
   register_lock_class+0x36d/0x540
   __lock_acquire+0x7f/0x1a30
   lock_acquire+0xcc/0x200
   del_timer_sync+0x3c/0xc0
   wb_domain_exit+0x14/0x20
   mem_cgroup_free+0x14/0x40
   mem_cgroup_css_alloc+0x3f9/0x620
   cgroup_apply_control_enable+0x190/0x390
   cgroup_mkdir+0x290/0x3d0
   kernfs_iop_mkdir+0x58/0x80
   vfs_mkdir+0x10e/0x1a0
   SyS_mkdirat+0xa8/0xd0
   SyS_mkdir+0x14/0x20
   entry_SYSCALL_64_fastpath+0x18/0xad

Add __mem_cgroup_free() which skips wb_domain_exit().  This is used by
both mem_cgroup_free() and mem_cgroup_alloc() clean up.

Fixes: 0b8f73e104 ("mm: memcontrol: clean up alloc, online, offline, free functions")
Link: http://lkml.kernel.org/r/20170306192122.24262-1-tahsin@google.com
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 17:01:10 -08:00
Kirill A. Shutemov
6ebb4a1b84 thp: fix another corner case of munlock() vs. THPs
The following test case triggers BUG() in munlock_vma_pages_range():

	int main(int argc, char *argv[])
	{
		int fd;

		system("mount -t tmpfs -o huge=always none /mnt");
		fd = open("/mnt/test", O_CREAT | O_RDWR);
		ftruncate(fd, 4UL << 20);
		mmap(NULL, 4UL << 20, PROT_READ | PROT_WRITE,
				MAP_SHARED | MAP_FIXED | MAP_LOCKED, fd, 0);
		mmap(NULL, 4096, PROT_READ | PROT_WRITE,
				MAP_SHARED | MAP_LOCKED, fd, 0);
		munlockall();
		return 0;
	}

The second mmap() create PTE-mapping of the first huge page in file.  It
makes kernel munlock the page as we never keep PTE-mapped page mlocked.

On munlockall() when we handle vma created by the first mmap(),
munlock_vma_page() returns page_mask == 0, as the page is not mlocked
anymore.  On next iteration follow_page_mask() return tail page, but
page_mask is HPAGE_NR_PAGES - 1.  It makes us skip to the first tail
page of the next huge page and step on
VM_BUG_ON_PAGE(PageMlocked(page)).

The fix is not use the page_mask from follow_page_mask() at all.  It has
no use for us.

Link: http://lkml.kernel.org/r/20170302150252.34120-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>    [4.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 17:01:10 -08:00
Kirill A. Shutemov
8346242a7e rmap: fix NULL-pointer dereference on THP munlocking
The following test case triggers NULL-pointer derefernce in
try_to_unmap_one():

	#include <fcntl.h>
	#include <stdlib.h>
	#include <unistd.h>
	#include <sys/mman.h>

	int main(int argc, char *argv[])
	{
		int fd;

		system("mount -t tmpfs -o huge=always none /mnt");
		fd = open("/mnt/test", O_CREAT | O_RDWR);
		ftruncate(fd, 2UL << 20);
		mmap(NULL, 2UL << 20, PROT_READ | PROT_WRITE,
				MAP_SHARED | MAP_FIXED | MAP_LOCKED, fd, 0);
		mmap(NULL, 2UL << 20, PROT_READ | PROT_WRITE,
				MAP_SHARED | MAP_LOCKED, fd, 0);
		munlockall();
		return 0;
	}

Apparently, there's a case when we call try_to_unmap() on huge PMDs:
it's TTU_MUNLOCK.

Let's handle this case correctly.

Fixes: c7ab0d2fdc ("mm: convert try_to_unmap_one() to use page_vma_mapped_walk()")
Link: http://lkml.kernel.org/r/20170302151159.30592-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 17:01:10 -08:00
AKASHI Takahiro
c9a1b80dae mm/memblock.c: fix memblock_next_valid_pfn()
Obviously, we should not access memblock.memory.regions[right] if
'right' is outside of [0..memblock.memory.cnt>.

Fixes: b92df1de5d ("mm: page_alloc: skip over regions of invalid pfns where possible")
Link: http://lkml.kernel.org/r/20170303023745.9104-1-takahiro.akashi@linaro.org
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 17:01:10 -08:00
Andrea Arcangeli
70ccb92fdd userfaultfd: non-cooperative: userfaultfd_remove revalidate vma in MADV_DONTNEED
userfaultfd_remove() has to be execute before zapping the pagetables or
UFFDIO_COPY could keep filling pages after zap_page_range returned,
which would result in non zero data after a MADV_DONTNEED.

However userfaultfd_remove() may have to release the mmap_sem.  This was
handled correctly in MADV_REMOVE, but MADV_DONTNEED accessed a
potentially stale vma (the very vma passed to zap_page_range(vma, ...)).

The fix consists in revalidating the vma in case userfaultfd_remove()
had to release the mmap_sem.

This also optimizes away an unnecessary down_read/up_read in the
MADV_REMOVE case if UFFD_EVENT_FORK had to be delivered.

It all remains zero runtime cost in case CONFIG_USERFAULTFD=n as
userfaultfd_remove() will be defined as "true" at build time.

Link: http://lkml.kernel.org/r/20170302173738.18994-3-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 17:01:10 -08:00
Laurent Dufour
bfc7228b9a mm/cgroup: avoid panic when init with low memory
The system may panic when initialisation is done when almost all the
memory is assigned to the huge pages using the kernel command line
parameter hugepage=xxxx.  Panic may occur like this:

  Unable to handle kernel paging request for data at address 0x00000000
  Faulting instruction address: 0xc000000000302b88
  Oops: Kernel access of bad area, sig: 11 [#1]
  SMP NR_CPUS=2048 [    0.082424] NUMA
  pSeries
  Modules linked in:
  CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.9.0-15-generic #16-Ubuntu
  task: c00000021ed01600 task.stack: c00000010d108000
  NIP: c000000000302b88 LR: c000000000270e04 CTR: c00000000016cfd0
  REGS: c00000010d10b2c0 TRAP: 0300   Not tainted (4.9.0-15-generic)
  MSR: 8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE>[ 0.082770]   CR: 28424422  XER: 00000000
  CFAR: c0000000003d28b8 DAR: 0000000000000000 DSISR: 40000000 SOFTE: 1
  GPR00: c000000000270e04 c00000010d10b540 c00000000141a300 c00000010fff6300
  GPR04: 0000000000000000 00000000026012c0 c00000010d10b630 0000000487ab0000
  GPR08: 000000010ee90000 c000000001454fd8 0000000000000000 0000000000000000
  GPR12: 0000000000004400 c00000000fb80000 00000000026012c0 00000000026012c0
  GPR16: 00000000026012c0 0000000000000000 0000000000000000 0000000000000002
  GPR20: 000000000000000c 0000000000000000 0000000000000000 00000000024200c0
  GPR24: c0000000016eef48 0000000000000000 c00000010fff7d00 00000000026012c0
  GPR28: 0000000000000000 c00000010fff7d00 c00000010fff6300 c00000010d10b6d0
  NIP mem_cgroup_soft_limit_reclaim+0xf8/0x4f0
  LR do_try_to_free_pages+0x1b4/0x450
  Call Trace:
    do_try_to_free_pages+0x1b4/0x450
    try_to_free_pages+0xf8/0x270
    __alloc_pages_nodemask+0x7a8/0xff0
    new_slab+0x104/0x8e0
    ___slab_alloc+0x620/0x700
    __slab_alloc+0x34/0x60
    kmem_cache_alloc_node_trace+0xdc/0x310
    mem_cgroup_init+0x158/0x1c8
    do_one_initcall+0x68/0x1d0
    kernel_init_freeable+0x278/0x360
    kernel_init+0x24/0x170
    ret_from_kernel_thread+0x5c/0x74
  Instruction dump:
  eb81ffe0 eba1ffe8 ebc1fff0 ebe1fff8 4e800020 3d230001 e9499a42 3d220004
  3929acd8 794a1f24 7d295214 eac90100 <e9360000> 2fa90000 419eff74 3b200000
  ---[ end trace 342f5208b00d01b6 ]---

This is a chicken and egg issue where the kernel try to get free memory
when allocating per node data in mem_cgroup_init(), but in that path
mem_cgroup_soft_limit_reclaim() is called which assumes that these data
are allocated.

As mem_cgroup_soft_limit_reclaim() is best effort, it should return when
these data are not yet allocated.

This patch also fixes potential null pointer access in
mem_cgroup_remove_from_trees() and mem_cgroup_update_tree().

Link: http://lkml.kernel.org/r/1487856999-16581-2-git-send-email-ldufour@linux.vnet.ibm.com
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 17:01:10 -08:00
Yisheng Xie
ce9311cf95 mm/vmstats: add thp_split_pud event for clarity
We added support for PUD-sized transparent hugepages, however we count
the event "thp split pud" into thp_split_pmd event.

To separate the event count of thp split pud from pmd, add a new event
named thp_split_pud.

Link: http://lkml.kernel.org/r/1488282380-5076-1-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 17:01:10 -08:00
Linus Torvalds
34bbce9e34 Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
 "Sending this a bit sooner than I otherwise would have, as a fix in the
  merge window had some unfortunate issues and side effects for some
  folks.

  This contains:

   - Fixes from Jan for the bdi registration/unregistration. These have
     been tested by the various parties reporting issues, and should be
     solid at this point.

   - Also from Jan, fix for axonram gendisk registration.

   - A stable fix for zram from Johannes.

   - A small series from Ming, fixing up some long standing issues with
     blk-mq hardware queue kobject initialization and registration.

   - A fix for sed opal from Jon, fixing a nonsensical range check and
     some set-but-not-used variables.

   - A fix from Neil for a long standing deadlock issue for stacking
     device drivers. With this in place, dm/md don't have to work around
     the issue anymore, and can be properly fixed up"

* 'for-linus' of git://git.kernel.dk/linux-block:
  axonram: Fix gendisk handling
  blk: improve order of bio handling in generic_make_request()
  Revert "scsi, block: fix duplicate bdi name registration crashes"
  block: Make del_gendisk() safer for disks without queues
  bdi: Fix use-after-free in wb_congested_put()
  block: Allow bdi re-registration
  block/sed: Fix opal user range check and unused variables
  zram: set physical queue limits to avoid array out of bounds accesses
  blk-mq: free hctx->cpumask in release handler of hctx's kobject
  blk-mq: make lifetime consistent between hctx and its kobject
  blk-mq: make lifetime consitent between q/ctx and its kobject
  blk-mq: initialize mq kobjects in blk_mq_init_allocated_queue()
2017-03-09 15:53:25 -08:00
Kirill A. Shutemov
90eceff1a3 mm: introduce __p4d_alloc()
For full 5-level paging we need a helper to allocate p4d page table.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 11:48:48 -08:00
Kirill A. Shutemov
c2febafc67 mm: convert generic code to 5-level paging
Convert all non-architecture-specific code to 5-level paging.

It's mostly mechanical adding handling one more page table level in
places where we deal with pud_t.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-09 11:48:47 -08:00
Tony Luck
b4fb8f66f1 mm, page_alloc: Add missing check for memory holes
Commit 13ad59df67 ("mm, page_alloc: avoid page_to_pfn() when merging
buddies") moved the check for memory holes out of page_is_buddy() and
had the callers do the check.

But this wasn't done correctly in one place which caused ia64 to crash
very early in boot.

Update to fix that and make ia64 boot again.

[ v2: Vlastimil pointed out we don't need to call page_to_pfn()
      since we already have the result of that in "buddy_pfn" ]

Fixes: 13ad59df67 ("avoid page_to_pfn() when merging buddies")
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-03-08 11:10:10 -08:00
Jan Kara
df23de5561 bdi: Fix use-after-free in wb_congested_put()
bdi_writeback_congested structures get created for each blkcg and bdi
regardless whether bdi is registered or not. When they are created in
unregistered bdi and the request queue (and thus bdi) is then destroyed
while blkg still holds reference to bdi_writeback_congested structure,
this structure will be referencing freed bdi and last wb_congested_put()
will try to remove the structure from already freed bdi.

With commit 165a5e22fa "block: Move bdi_unregister() to
del_gendisk()", SCSI started to destroy bdis without calling
bdi_unregister() first (previously it was calling bdi_unregister() even
for unregistered bdis) and thus the code detaching
bdi_writeback_congested in cgwb_bdi_destroy() was not triggered and we
started hitting this use-after-free bug. It is enough to boot a KVM
instance with virtio-scsi device to trigger this behavior.

Fix the problem by detaching bdi_writeback_congested structures in
bdi_exit() instead of bdi_unregister(). This is also more logical as
they can get attached to bdi regardless whether it ever got registered
or not.

Fixes: 165a5e22fa
Signed-off-by: Jan Kara <jack@suse.cz>
Tested-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-08 10:55:17 -07:00
Jan Kara
b6f8fec444 block: Allow bdi re-registration
SCSI can call device_add_disk() several times for one request queue when
a device in unbound and bound, creating new gendisk each time. This will
lead to bdi being repeatedly registered and unregistered. This was not a
big problem until commit 165a5e22fa "block: Move bdi_unregister() to
del_gendisk()" since bdi was only registered repeatedly (bdi_register()
handles repeated calls fine, only we ended up leaking reference to
gendisk due to overwriting bdi->owner) but unregistered only in
blk_cleanup_queue() which didn't get called repeatedly. After
165a5e22fa we were doing correct bdi_register() - bdi_unregister()
cycles however bdi_unregister() is not prepared for it. So make sure
bdi_unregister() cleans up bdi in such a way that it is prepared for
a possible following bdi_register() call.

An easy way to provoke this behavior is to enable
CONFIG_DEBUG_TEST_DRIVER_REMOVE and use scsi_debug driver to create a
scsi disk which immediately hangs without this fix.

Fixes: 165a5e22fa
Signed-off-by: Jan Kara <jack@suse.cz>
Tested-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-08 10:55:17 -07:00
Tahsin Erdogan
8a1df543de percpu: remove unused chunk_alloc parameter from pcpu_get_pages()
pcpu_get_pages() doesn't use chunk_alloc parameter, remove it.

Fixes: fbbb7f4e14 ("percpu: remove the usage of separate populated bitmap in percpu-vm")
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2017-03-06 15:56:55 -05:00
Tahsin Erdogan
320661b08d percpu: acquire pcpu_lock when updating pcpu_nr_empty_pop_pages
Update to pcpu_nr_empty_pop_pages in pcpu_alloc() is currently done
without holding pcpu_lock. This can lead to bad updates to the variable.
Add missing lock calls.

Fixes: b539b87fed ("percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated")
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # v3.18+
2017-03-06 15:55:39 -05:00
Linus Torvalds
590dce2d49 Merge branch 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs 'statx()' update from Al Viro.

This adds the new extended stat() interface that internally subsumes our
previous stat interfaces, and allows user mode to specify in more detail
what kind of information it wants.

It also allows for some explicit synchronization information to be
passed to the filesystem, which can be relevant for network filesystems:
is the cached value ok, or do you need open/close consistency, or what?

From David Howells.

Andreas Dilger points out that the first version of the extended statx
interface was posted June 29, 2010:

    https://www.spinics.net/lists/linux-fsdevel/msg33831.html

* 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  statx: Add a system call to make enhanced file info available
2017-03-03 11:38:56 -08:00
Linus Torvalds
1827adb11a Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull sched.h split-up from Ingo Molnar:
 "The point of these changes is to significantly reduce the
  <linux/sched.h> header footprint, to speed up the kernel build and to
  have a cleaner header structure.

  After these changes the new <linux/sched.h>'s typical preprocessed
  size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K
  lines), which is around 40% faster to build on typical configs.

  Not much changed from the last version (-v2) posted three weeks ago: I
  eliminated quirks, backmerged fixes plus I rebased it to an upstream
  SHA1 from yesterday that includes most changes queued up in -next plus
  all sched.h changes that were pending from Andrew.

  I've re-tested the series both on x86 and on cross-arch defconfigs,
  and did a bisectability test at a number of random points.

  I tried to test as many build configurations as possible, but some
  build breakage is probably still left - but it should be mostly
  limited to architectures that have no cross-compiler binaries
  available on kernel.org, and non-default configurations"

* 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits)
  sched/headers: Clean up <linux/sched.h>
  sched/headers: Remove #ifdefs from <linux/sched.h>
  sched/headers: Remove the <linux/topology.h> include from <linux/sched.h>
  sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h>
  sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h>
  sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h>
  sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/init.h>
  sched/core: Remove unused prefetch_stack()
  sched/headers: Remove <linux/rculist.h> from <linux/sched.h>
  sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h>
  sched/headers: Remove <linux/signal.h> from <linux/sched.h>
  sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>
  sched/headers: Remove the runqueue_is_locked() prototype
  sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h>
  sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h>
  sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h>
  sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h>
  ...
2017-03-03 10:16:38 -08:00
David Howells
a528d35e8b statx: Add a system call to make enhanced file info available
Add a system call to make extended file information available, including
file creation and some attribute flags where available through the
underlying filesystem.

The getattr inode operation is altered to take two additional arguments: a
u32 request_mask and an unsigned int flags that indicate the
synchronisation mode.  This change is propagated to the vfs_getattr*()
function.

Functions like vfs_stat() are now inline wrappers around new functions
vfs_statx() and vfs_statx_fd() to reduce stack usage.

========
OVERVIEW
========

The idea was initially proposed as a set of xattrs that could be retrieved
with getxattr(), but the general preference proved to be for a new syscall
with an extended stat structure.

A number of requests were gathered for features to be included.  The
following have been included:

 (1) Make the fields a consistent size on all arches and make them large.

 (2) Spare space, request flags and information flags are provided for
     future expansion.

 (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an
     __s64).

 (4) Creation time: The SMB protocol carries the creation time, which could
     be exported by Samba, which will in turn help CIFS make use of
     FS-Cache as that can be used for coherency data (stx_btime).

     This is also specified in NFSv4 as a recommended attribute and could
     be exported by NFSD [Steve French].

 (5) Lightweight stat: Ask for just those details of interest, and allow a
     netfs (such as NFS) to approximate anything not of interest, possibly
     without going to the server [Trond Myklebust, Ulrich Drepper, Andreas
     Dilger] (AT_STATX_DONT_SYNC).

 (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks
     its cached attributes are up to date [Trond Myklebust]
     (AT_STATX_FORCE_SYNC).

And the following have been left out for future extension:

 (7) Data version number: Could be used by userspace NFS servers [Aneesh
     Kumar].

     Can also be used to modify fill_post_wcc() in NFSD which retrieves
     i_version directly, but has just called vfs_getattr().  It could get
     it from the kstat struct if it used vfs_xgetattr() instead.

     (There's disagreement on the exact semantics of a single field, since
     not all filesystems do this the same way).

 (8) BSD stat compatibility: Including more fields from the BSD stat such
     as creation time (st_btime) and inode generation number (st_gen)
     [Jeremy Allison, Bernd Schubert].

 (9) Inode generation number: Useful for FUSE and userspace NFS servers
     [Bernd Schubert].

     (This was asked for but later deemed unnecessary with the
     open-by-handle capability available and caused disagreement as to
     whether it's a security hole or not).

(10) Extra coherency data may be useful in making backups [Andreas Dilger].

     (No particular data were offered, but things like last backup
     timestamp, the data version number and the DOS archive bit would come
     into this category).

(11) Allow the filesystem to indicate what it can/cannot provide: A
     filesystem can now say it doesn't support a standard stat feature if
     that isn't available, so if, for instance, inode numbers or UIDs don't
     exist or are fabricated locally...

     (This requires a separate system call - I have an fsinfo() call idea
     for this).

(12) Store a 16-byte volume ID in the superblock that can be returned in
     struct xstat [Steve French].

     (Deferred to fsinfo).

(13) Include granularity fields in the time data to indicate the
     granularity of each of the times (NFSv4 time_delta) [Steve French].

     (Deferred to fsinfo).

(14) FS_IOC_GETFLAGS value.  These could be translated to BSD's st_flags.
     Note that the Linux IOC flags are a mess and filesystems such as Ext4
     define flags that aren't in linux/fs.h, so translation in the kernel
     may be a necessity (or, possibly, we provide the filesystem type too).

     (Some attributes are made available in stx_attributes, but the general
     feeling was that the IOC flags were to ext[234]-specific and shouldn't
     be exposed through statx this way).

(15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer,
     Michael Kerrisk].

     (Deferred, probably to fsinfo.  Finding out if there's an ACL or
     seclabal might require extra filesystem operations).

(16) Femtosecond-resolution timestamps [Dave Chinner].

     (A __reserved field has been left in the statx_timestamp struct for
     this - if there proves to be a need).

(17) A set multiple attributes syscall to go with this.

===============
NEW SYSTEM CALL
===============

The new system call is:

	int ret = statx(int dfd,
			const char *filename,
			unsigned int flags,
			unsigned int mask,
			struct statx *buffer);

The dfd, filename and flags parameters indicate the file to query, in a
similar way to fstatat().  There is no equivalent of lstat() as that can be
emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags.  There is
also no equivalent of fstat() as that can be emulated by passing a NULL
filename to statx() with the fd of interest in dfd.

Whether or not statx() synchronises the attributes with the backing store
can be controlled by OR'ing a value into the flags argument (this typically
only affects network filesystems):

 (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this
     respect.

 (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise
     its attributes with the server - which might require data writeback to
     occur to get the timestamps correct.

 (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a
     network filesystem.  The resulting values should be considered
     approximate.

mask is a bitmask indicating the fields in struct statx that are of
interest to the caller.  The user should set this to STATX_BASIC_STATS to
get the basic set returned by stat().  It should be noted that asking for
more information may entail extra I/O operations.

buffer points to the destination for the data.  This must be 256 bytes in
size.

======================
MAIN ATTRIBUTES RECORD
======================

The following structures are defined in which to return the main attribute
set:

	struct statx_timestamp {
		__s64	tv_sec;
		__s32	tv_nsec;
		__s32	__reserved;
	};

	struct statx {
		__u32	stx_mask;
		__u32	stx_blksize;
		__u64	stx_attributes;
		__u32	stx_nlink;
		__u32	stx_uid;
		__u32	stx_gid;
		__u16	stx_mode;
		__u16	__spare0[1];
		__u64	stx_ino;
		__u64	stx_size;
		__u64	stx_blocks;
		__u64	__spare1[1];
		struct statx_timestamp	stx_atime;
		struct statx_timestamp	stx_btime;
		struct statx_timestamp	stx_ctime;
		struct statx_timestamp	stx_mtime;
		__u32	stx_rdev_major;
		__u32	stx_rdev_minor;
		__u32	stx_dev_major;
		__u32	stx_dev_minor;
		__u64	__spare2[14];
	};

The defined bits in request_mask and stx_mask are:

	STATX_TYPE		Want/got stx_mode & S_IFMT
	STATX_MODE		Want/got stx_mode & ~S_IFMT
	STATX_NLINK		Want/got stx_nlink
	STATX_UID		Want/got stx_uid
	STATX_GID		Want/got stx_gid
	STATX_ATIME		Want/got stx_atime{,_ns}
	STATX_MTIME		Want/got stx_mtime{,_ns}
	STATX_CTIME		Want/got stx_ctime{,_ns}
	STATX_INO		Want/got stx_ino
	STATX_SIZE		Want/got stx_size
	STATX_BLOCKS		Want/got stx_blocks
	STATX_BASIC_STATS	[The stuff in the normal stat struct]
	STATX_BTIME		Want/got stx_btime{,_ns}
	STATX_ALL		[All currently available stuff]

stx_btime is the file creation time, stx_mask is a bitmask indicating the
data provided and __spares*[] are where as-yet undefined fields can be
placed.

Time fields are structures with separate seconds and nanoseconds fields
plus a reserved field in case we want to add even finer resolution.  Note
that times will be negative if before 1970; in such a case, the nanosecond
fields will also be negative if not zero.

The bits defined in the stx_attributes field convey information about a
file, how it is accessed, where it is and what it does.  The following
attributes map to FS_*_FL flags and are the same numerical value:

	STATX_ATTR_COMPRESSED		File is compressed by the fs
	STATX_ATTR_IMMUTABLE		File is marked immutable
	STATX_ATTR_APPEND		File is append-only
	STATX_ATTR_NODUMP		File is not to be dumped
	STATX_ATTR_ENCRYPTED		File requires key to decrypt in fs

Within the kernel, the supported flags are listed by:

	KSTAT_ATTR_FS_IOC_FLAGS

[Are any other IOC flags of sufficient general interest to be exposed
through this interface?]

New flags include:

	STATX_ATTR_AUTOMOUNT		Object is an automount trigger

These are for the use of GUI tools that might want to mark files specially,
depending on what they are.

Fields in struct statx come in a number of classes:

 (0) stx_dev_*, stx_blksize.

     These are local system information and are always available.

 (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino,
     stx_size, stx_blocks.

     These will be returned whether the caller asks for them or not.  The
     corresponding bits in stx_mask will be set to indicate whether they
     actually have valid values.

     If the caller didn't ask for them, then they may be approximated.  For
     example, NFS won't waste any time updating them from the server,
     unless as a byproduct of updating something requested.

     If the values don't actually exist for the underlying object (such as
     UID or GID on a DOS file), then the bit won't be set in the stx_mask,
     even if the caller asked for the value.  In such a case, the returned
     value will be a fabrication.

     Note that there are instances where the type might not be valid, for
     instance Windows reparse points.

 (2) stx_rdev_*.

     This will be set only if stx_mode indicates we're looking at a
     blockdev or a chardev, otherwise will be 0.

 (3) stx_btime.

     Similar to (1), except this will be set to 0 if it doesn't exist.

=======
TESTING
=======

The following test program can be used to test the statx system call:

	samples/statx/test-statx.c

Just compile and run, passing it paths to the files you want to examine.
The file is built automatically if CONFIG_SAMPLES is enabled.

Here's some example output.  Firstly, an NFS directory that crosses to
another FSID.  Note that the AUTOMOUNT attribute is set because transiting
this directory will cause d_automount to be invoked by the VFS.

	[root@andromeda ~]# /tmp/test-statx -A /warthog/data
	statx(/warthog/data) = 0
	results=7ff
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:26           Inode: 1703937     Links: 125
	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
	Access: 2016-11-24 09:02:12.219699527+0000
	Modify: 2016-11-17 10:44:36.225653653+0000
	Change: 2016-11-17 10:44:36.225653653+0000
	Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------)

Secondly, the result of automounting on that directory.

	[root@andromeda ~]# /tmp/test-statx /warthog/data
	statx(/warthog/data) = 0
	results=7ff
	  Size: 4096            Blocks: 8          IO Block: 1048576  directory
	Device: 00:27           Inode: 2           Links: 125
	Access: (3777/drwxrwxrwx)  Uid:     0   Gid:  4041
	Access: 2016-11-24 09:02:12.219699527+0000
	Modify: 2016-11-17 10:44:36.225653653+0000
	Change: 2016-11-17 10:44:36.225653653+0000

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-02 20:51:15 -05:00
Ingo Molnar
c3edc4010e sched/headers: Move task_struct::signal and task_struct::sighand types and accessors into <linux/sched/signal.h>
task_struct::signal and task_struct::sighand are pointers, which would normally make it
straightforward to not define those types in sched.h.

That is not so, because the types are accompanied by a myriad of APIs (macros and inline
functions) that dereference them.

Split the types and the APIs out of sched.h and move them into a new header, <linux/sched/signal.h>.

With this change sched.h does not know about 'struct signal' and 'struct sighand' anymore,
trying to put accessors into sched.h as a test fails the following way:

  ./include/linux/sched.h: In function ‘test_signal_types’:
  ./include/linux/sched.h:2461:18: error: dereferencing pointer to incomplete type ‘struct signal_struct’
                    ^

This reduces the size and complexity of sched.h significantly.

Update all headers and .c code that relied on getting the signal handling
functionality from <linux/sched.h> to include <linux/sched/signal.h>.

The list of affected files in the preparatory patch was partly generated by
grepping for the APIs, and partly by doing coverage build testing, both
all[yes|mod|def|no]config builds on 64-bit and 32-bit x86, and an array of
cross-architecture builds.

Nevertheless some (trivial) build breakage is still expected related to rare
Kconfig combinations and in-flight patches to various kernel code, but most
of it should be handled by this patch.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-03 01:43:37 +01:00
Linus Torvalds
94e877d0fb Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs pile two from Al Viro:

 - orangefs fix

 - series of fs/namei.c cleanups from me

 - VFS stuff coming from overlayfs tree

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  orangefs: Use RCU for destroy_inode
  vfs: use helper for calling f_op->fsync()
  mm: use helper for calling f_op->mmap()
  vfs: use helpers for calling f_op->{read,write}_iter()
  vfs: pass type instead of fn to do_{loop,iter}_readv_writev()
  vfs: extract common parts of {compat_,}do_readv_writev()
  vfs: wrap write f_ops with file_{start,end}_write()
  vfs: deny copy_file_range() for non regular files
  vfs: deny fallocate() on directory
  vfs: create vfs helper vfs_tmpfile()
  namei.c: split unlazy_walk()
  namei.c: fold the check for DCACHE_OP_REVALIDATE into d_revalidate()
  lookup_fast(): clean up the logics around the fallback to non-rcu mode
  namei: fold unlazy_link() into its sole caller
2017-03-02 15:20:00 -08:00
Al Viro
653a7746fa Merge remote-tracking branch 'ovl/for-viro' into for-linus
Overlayfs-related series from Miklos and Amir
2017-03-02 06:41:22 -05:00
Ingo Molnar
50d34394ce sched/headers: Prepare to remove the <linux/magic.h> include from <linux/sched/task_stack.h>
Update files that depend on the magic.h inclusion.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:40 +01:00
Ingo Molnar
3f8c24529b sched/headers: Prepare to move kstack_end() from <linux/sched.h> to <linux/sched/task_stack.h>
But first update the usage sites with the new header dependency.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:39 +01:00
Ingo Molnar
f719ff9bce sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h>
But first update the code that uses these facilities with the
new header.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:38 +01:00
Ingo Molnar
9164bb4a18 sched/headers: Prepare to move 'init_task' and 'init_thread_union' from <linux/sched.h> to <linux/sched/task.h>
Update all usage sites first.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:38 +01:00
Ingo Molnar
f361bf4a66 sched/headers: Prepare for the reduction of <linux/sched.h>'s signal API dependency
Instead of including the full <linux/signal.h>, we are going to include the
types-only <linux/signal_types.h> header in <linux/sched.h>, to further
decouple the scheduler header from the signal headers.

This means that various files which relied on the full <linux/signal.h> need
to be updated to gain an explicit dependency on it.

Update the code that relies on sched.h's inclusion of the <linux/signal.h> header.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:37 +01:00
Ingo Molnar
68db0cf106 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task_stack.h>
We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:36 +01:00
Ingo Molnar
299300258d sched/headers: Prepare for new header dependencies before moving code to <linux/sched/task.h>
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/task.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:35 +01:00
Ingo Molnar
5b3cc15aff sched/headers: Prepare to move the memalloc_noio_*() APIs to <linux/sched/mm.h>
Update the .c files that depend on these APIs.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:33 +01:00
Ingo Molnar
174cd4b1e5 sched/headers: Prepare to move signal wakeup & sigpending methods from <linux/sched.h> into <linux/sched/signal.h>
Fix up affected files that include this signal functionality via sched.h.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:32 +01:00
Ingo Molnar
5b825c3af1 sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>
Add #include <linux/cred.h> dependencies to all .c files rely on sched.h
doing that for them.

Note that even if the count where we need to add extra headers seems high,
it's still a net win, because <linux/sched.h> is included in over
2,200 files ...

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:31 +01:00
Ingo Molnar
6a3827d750 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/numa_balancing.h>
We are going to split <linux/sched/numa_balancing.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/numa_balancing.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:30 +01:00
Ingo Molnar
8703e8a465 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/user.h>
We are going to split <linux/sched/user.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/user.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:29 +01:00
Ingo Molnar
3f07c01441 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:29 +01:00
Ingo Molnar
f7ccbae45c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/coredump.h>
We are going to split <linux/sched/coredump.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/coredump.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:28 +01:00
Ingo Molnar
6e84f31522 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/mm.h>
We are going to split <linux/sched/mm.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/mm.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

The APIs that are going to be moved first are:

   mm_alloc()
   __mmdrop()
   mmdrop()
   mmdrop_async_fn()
   mmdrop_async()
   mmget_not_zero()
   mmput()
   mmput_async()
   get_task_mm()
   mm_access()
   mm_release()

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:28 +01:00
Ingo Molnar
af8601ad42 kasan, sched/headers: Uninline kasan_enable/disable_current()
<linux/kasan.h> is a low level header that is included early
in affected kernel headers. But it includes <linux/sched.h>
which complicates the cleanup of sched.h dependencies.

But kasan.h has almost no need for sched.h: its only use of
scheduler functionality is in two inline functions which are
not used very frequently - so uninline kasan_enable_current()
and kasan_disable_current().

Also add a <linux/sched.h> dependency to a .c file that depended
on kasan.h including it.

This paves the way to remove the <linux/sched.h> include from kasan.h.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:25 +01:00
Ingo Molnar
314ff7851f mm/vmacache, sched/headers: Introduce 'struct vmacache' and move it from <linux/sched.h> to <linux/mm_types>
The <linux/sched.h> header includes various vmacache related defines,
which are arguably misplaced.

Move them to mm_types.h and minimize the sched.h impact by putting
all task vmacache state into a new 'struct vmacache' structure.

No change in functionality.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:25 +01:00
Linus Torvalds
cf393195c3 Merge branch 'idr-4.11' of git://git.infradead.org/users/willy/linux-dax
Pull IDR rewrite from Matthew Wilcox:
 "The most significant part of the following is the patch to rewrite the
  IDR & IDA to be clients of the radix tree. But there's much more,
  including an enhancement of the IDA to be significantly more space
  efficient, an IDR & IDA test suite, some improvements to the IDR API
  (and driver changes to take advantage of those improvements), several
  improvements to the radix tree test suite and RCU annotations.

  The IDR & IDA rewrite had a good spin in linux-next and Andrew's tree
  for most of the last cycle. Coupled with the IDR test suite, I feel
  pretty confident that any remaining bugs are quite hard to hit. 0-day
  did a great job of watching my git tree and pointing out problems; as
  it hit them, I added new test-cases to be sure not to be caught the
  same way twice"

Willy goes on to expand a bit on the IDR rewrite rationale:
 "The radix tree and the IDR use very similar data structures.

  Merging the two codebases lets us share the memory allocation pools,
  and results in a net deletion of 500 lines of code. It also opens up
  the possibility of exposing more of the features of the radix tree to
  users of the IDR (and I have some interesting patches along those
  lines waiting for 4.12)

  It also shrinks the size of the 'struct idr' from 40 bytes to 24 which
  will shrink a fair few data structures that embed an IDR"

* 'idr-4.11' of git://git.infradead.org/users/willy/linux-dax: (32 commits)
  radix tree test suite: Add config option for map shift
  idr: Add missing __rcu annotations
  radix-tree: Fix __rcu annotations
  radix-tree: Add rcu_dereference and rcu_assign_pointer calls
  radix tree test suite: Run iteration tests for longer
  radix tree test suite: Fix split/join memory leaks
  radix tree test suite: Fix leaks in regression2.c
  radix tree test suite: Fix leaky tests
  radix tree test suite: Enable address sanitizer
  radix_tree_iter_resume: Fix out of bounds error
  radix-tree: Store a pointer to the root in each node
  radix-tree: Chain preallocated nodes through ->parent
  radix tree test suite: Dial down verbosity with -v
  radix tree test suite: Introduce kmalloc_verbose
  idr: Return the deleted entry from idr_remove
  radix tree test suite: Build separate binaries for some tests
  ida: Use exceptional entries for small IDAs
  ida: Move ida_bitmap to a percpu variable
  Reimplement IDR and IDA using the radix tree
  radix-tree: Add radix_tree_iter_delete
  ...
2017-02-28 20:29:41 -08:00
Jinbum Park
2959a5f726 mm: add arch-independent testcases for RODATA
This patch makes arch-independent testcases for RODATA.  Both x86 and
x86_64 already have testcases for RODATA, But they are arch-specific
because using inline assembly directly.

And cacheflush.h is not a suitable location for rodata-test related
things.  Since they were in cacheflush.h, If someone change the state of
CONFIG_DEBUG_RODATA_TEST, It cause overhead of kernel build.

To solve the above issues, write arch-independent testcases and move it
to shared location.

[jinb.park7@gmail.com: fix config dependency]
  Link: http://lkml.kernel.org/r/20170209131625.GA16954@pjb1027-Latitude-E5410
Link: http://lkml.kernel.org/r/20170129105436.GA9303@pjb1027-Latitude-E5410
Signed-off-by: Jinbum Park <jinb.park7@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Valentin Rothberg <valentinrothberg@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:48 -08:00
Vegard Nossum
388f793455 mm: use mmget_not_zero() helper
We already have the helper, we can convert the rest of the kernel
mechanically using:

  git grep -l 'atomic_inc_not_zero.*mm_users' | xargs sed -i 's/atomic_inc_not_zero(&\(.*\)->mm_users)/mmget_not_zero\(\1\)/'

This is needed for a later patch that hooks into the helper, but might
be a worthwhile cleanup on its own.

Link: http://lkml.kernel.org/r/20161218123229.22952-3-vegard.nossum@oracle.com
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:48 -08:00
Vegard Nossum
3fce371bfa mm: add new mmget() helper
Apart from adding the helper function itself, the rest of the kernel is
converted mechanically using:

  git grep -l 'atomic_inc.*mm_users' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_users);/mmget\(\1\);/'
  git grep -l 'atomic_inc.*mm_users' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_users);/mmget\(\&\1\);/'

This is needed for a later patch that hooks into the helper, but might
be a worthwhile cleanup on its own.

(Michal Hocko provided most of the kerneldoc comment.)

Link: http://lkml.kernel.org/r/20161218123229.22952-2-vegard.nossum@oracle.com
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:48 -08:00
Vegard Nossum
f1f1007644 mm: add new mmgrab() helper
Apart from adding the helper function itself, the rest of the kernel is
converted mechanically using:

  git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)->mm_count);/mmgrab\(\1\);/'
  git grep -l 'atomic_inc.*mm_count' | xargs sed -i 's/atomic_inc(&\(.*\)\.mm_count);/mmgrab\(\&\1\);/'

This is needed for a later patch that hooks into the helper, but might
be a worthwhile cleanup on its own.

(Michal Hocko provided most of the kerneldoc comment.)

Link: http://lkml.kernel.org/r/20161218123229.22952-1-vegard.nossum@oracle.com
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:48 -08:00
Alexey Dobriyan
5b5e0928f7 lib/vsprintf.c: remove %Z support
Now that %z is standartised in C99 there is no reason to support %Z.
Unlike %L it doesn't even make format strings smaller.

Use BUILD_BUG_ON in a couple ATM drivers.

In case anyone didn't notice lib/vsprintf.o is about half of SLUB which
is in my opinion is quite an achievement.  Hopefully this patch inspires
someone else to trim vsprintf.c more.

Link: http://lkml.kernel.org/r/20170103230126.GA30170@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:47 -08:00
Masahiro Yamada
4091fb95b5 scripts/spelling.txt: add "followings" pattern and fix typo instances
Fix typos and add the following to the scripts/spelling.txt:

  followings||following

While we are here, add a missing colon in the boilerplate in DT binding
documents.  The "you SoC" in allwinner,sunxi-pinctrl.txt was fixed as
well.

I reworded "as the followings:" to "as follows:" for
drivers/usb/gadget/udc/renesas_usb3.c.

Link: http://lkml.kernel.org/r/1481573103-11329-32-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:47 -08:00
Masahiro Yamada
3f8b6fb7f2 scripts/spelling.txt: add "comsume(r)" pattern and fix typo instances
Fix typos and add the following to the scripts/spelling.txt:

  comsume||consume
  comsumer||consumer
  comsuming||consuming

I see some variable names with this pattern, but this commit is only
touching comment blocks to avoid unexpected impact.

Link: http://lkml.kernel.org/r/1481573103-11329-19-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:47 -08:00
Masahiro Yamada
89d790ab31 scripts/spelling.txt: add "algined" pattern and fix typo instances
Fix typos and add the following to the scripts/spelling.txt:

  algined||aligned

While we are here, fix the "appplication" in the touched line in
drivers/block/loop.c.  Also, fix the "may not naturally ..." to
"may not be naturally ..." in the touched line in mm/page_alloc.

Link: http://lkml.kernel.org/r/1481573103-11329-9-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:46 -08:00
Fabian Frederick
93407472a2 fs: add i_blocksize()
Replace all 1 << inode->i_blkbits and (1 << inode->i_blkbits) in fs
branch.

This patch also fixes multiple checkpatch warnings: WARNING: Prefer
'unsigned int' to bare use of 'unsigned'

Thanks to Andrew Morton for suggesting more appropriate function instead
of macro.

[geliangtang@gmail.com: truncate: use i_blocksize()]
  Link: http://lkml.kernel.org/r/9c8b2cd83c8f5653805d43debde9fa8817e02fc4.1484895804.git.geliangtang@gmail.com
Link: http://lkml.kernel.org/r/1481319905-10126-1-git-send-email-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:46 -08:00
Dan Streetman
fd5bb66cd9 zswap: don't param_set_charp while holding spinlock
Change the zpool/compressor param callback function to release the
zswap_pools_lock spinlock before calling param_set_charp, since that
function may sleep when it calls kmalloc with GFP_KERNEL.

While this problem has existed for a while, I wasn't able to trigger it
using a tight loop changing either/both the zpool and compressor params; I
think it's very unlikely to be an issue on the stable kernels, especially
since most zswap users will change the compressor and/or zpool from sysfs
only one time each boot - or zero times, if they add the params to the
kernel boot.

Fixes: c99b42c352 ("zswap: use charp for zswap param strings")
Link: http://lkml.kernel.org/r/20170126155821.4545-1-ddstreet@ieee.org
Signed-off-by: Dan Streetman <dan.streetman@canonical.com>
Reported-by: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:45 -08:00
Dan Streetman
bae21db88b zswap: clear compressor or zpool param if invalid at init
If either the compressor and/or zpool param are invalid at boot, and
their default value is also invalid, set the param to the empty string
to indicate there is no compressor and/or zpool configured.  This allows
users to check the sysfs interface to see which param needs changing.

Link: http://lkml.kernel.org/r/20170124200259.16191-4-ddstreet@ieee.org
Signed-off-by: Dan Streetman <dan.streetman@canonical.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:45 -08:00
Dan Streetman
ae3d89a7e0 zswap: allow initialization at boot without pool
Allow zswap to initialize at boot even if it can't create its pool due
to a failure to create a zpool and/or compressor.  Allow those to be
created later, from the sysfs module param interface.

Link: http://lkml.kernel.org/r/20170124200259.16191-3-ddstreet@ieee.org
Signed-off-by: Dan Streetman <dan.streetman@canonical.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:45 -08:00
Greg Thelen
f9fa1d919c kasan: drain quarantine of memcg slab objects
Per memcg slab accounting and kasan have a problem with kmem_cache
destruction.
 - kmem_cache_create() allocates a kmem_cache, which is used for
   allocations from processes running in root (top) memcg.
 - Processes running in non root memcg and allocating with either
   __GFP_ACCOUNT or from a SLAB_ACCOUNT cache use a per memcg
   kmem_cache.
 - Kasan catches use-after-free by having kfree() and kmem_cache_free()
   defer freeing of objects. Objects are placed in a quarantine.
 - kmem_cache_destroy() destroys root and non root kmem_caches. It takes
   care to drain the quarantine of objects from the root memcg's
   kmem_cache, but ignores objects associated with non root memcg. This
   causes leaks because quarantined per memcg objects refer to per memcg
   kmem cache being destroyed.

To see the problem:

 1) create a slab cache with kmem_cache_create(,,,SLAB_ACCOUNT,)
 2) from non root memcg, allocate and free a few objects from cache
 3) dispose of the cache with kmem_cache_destroy() kmem_cache_destroy()
    will trigger a "Slab cache still has objects" warning indicating
    that the per memcg kmem_cache structure was leaked.

Fix the leak by draining kasan quarantined objects allocated from non
root memcg.

Racing memcg deletion is tricky, but handled.  kmem_cache_destroy() =>
shutdown_memcg_caches() => __shutdown_memcg_cache() => shutdown_cache()
flushes per memcg quarantined objects, even if that memcg has been
rmdir'd and gone through memcg_deactivate_kmem_caches().

This leak only affects destroyed SLAB_ACCOUNT kmem caches when kasan is
enabled.  So I don't think it's worth patching stable kernels.

Link: http://lkml.kernel.org/r/1482257462-36948-1-git-send-email-gthelen@google.com
Signed-off-by: Greg Thelen <gthelen@google.com>
Reviewed-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Nathan Fontenot
dc18d706a4 memory-hotplug: use dev_online for memhp_auto_online
Commit 31bc3858ea ("add automatic onlining policy for the newly added
memory") provides the capability to have added memory automatically
onlined during add, but this appears to be slightly broken.

The current implementation uses walk_memory_range() to call
online_memory_block, which uses memory_block_change_state() to online
the memory.  Instead, we should be calling device_online() for the
memory block in online_memory_block().  This would online the memory
(the memory bus online routine memory_subsys_online() called from
device_online calls memory_block_change_state()) and properly update the
device struct offline flag.

As a result of the current implementation, attempting to remove a memory
block after adding it using auto online fails.  This is because doing a
remove, for instance

  echo offline > /sys/devices/system/memory/memoryXXX/state

uses device_offline() which checks the dev->offline flag.

Link: http://lkml.kernel.org/r/20170222220744.8119.19687.stgit@ltcalpine2-lp14.aus.stglabs.ibm.com
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Minchan Kim
dd8416c477 mm: do not access page->mapping directly on page_endio
With rw_page, page_endio is used for completing IO on a page and it
propagates write error to the address space if the IO fails.  The
problem is it accesses page->mapping directly which might be okay for
file-backed pages but it shouldn't for anonymous page.  Otherwise, it
can corrupt one of field from anon_vma under us and system goes panic
randomly.

swap_writepage
  bdev_writepage
    ops->rw_page

I encountered the BUG during developing new zram feature and it was
really hard to figure it out because it made random crash, somtime
mmap_sem lockdep, sometime other places where places never related to
zram/zsmalloc, and not reproducible with some configuration.

When I consider how that bug is subtle and people do fast-swap test with
brd, it's worth to add stable mark, I think.

Fixes: dd6bd0d9c7 ("swap: use bdev_read_page() / bdev_write_page()")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Aneesh Kumar K.V
9a8b300f2f mm/thp/autonuma: use TNF flag instead of vm fault
We are using the wrong flag value in task_numa_falt function.  This can
result in us doing wrong numa fault statistics update, because we update
num_pages_migrate and numa_fault_locality etc based on the flag argument
passed.

Fixes: bae473a423 ("mm: introduce fault_env")
Link: http://lkml.kernel.org/r/1487498395-9544-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Aneesh Kumar K.V
db08f2030a mm/gup: check for protnone only if it is a PTE entry
Do the prot_none/FOLL_NUMA check after we are sure this is a THP pte.
Archs can implement prot_none such that it can return true for regular
pmd entries.

Link: http://lkml.kernel.org/r/1487498326-8734-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Miles Chen
199eaa05ad mm: cleanups for printing phys_addr_t and dma_addr_t
cleanup rest of dma_addr_t and phys_addr_t type casting in mm
use %pad for dma_addr_t
use %pa for phys_addr_t

Link: http://lkml.kernel.org/r/1486618489-13912-1-git-send-email-miles.chen@mediatek.com
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Yisheng Xie
b538e422e4 mm/zsmalloc: fix comment in zsmalloc
The class index and fullness group are not encoded in
(first)page->mapping any more, after commit 3783689a1a ("zsmalloc:
introduce zspage structure").  Instead, they are store in struct zspage.

Just delete this unneeded comment.

Link: http://lkml.kernel.org/r/1486620822-36826-1-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Wei Yang
ad69444e75 mm/page_alloc.c: remove redundant init code for ZONE_MOVABLE
arch_zone_lowest/highest_possible_pfn[] is set to 0 and [ZONE_MOVABLE]
is skipped in the loop.  No need to reset them to 0 again.

This patch just removes the redundant code.

Link: http://lkml.kernel.org/r/20170209141731.60208-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Yisheng Xie
22c5cef162 mm/zsmalloc: remove redundant SetPagePrivate2 in create_page_chain
We had used page->lru to link the component pages (except the first
page) of a zspage, and used INIT_LIST_HEAD(&page->lru) to init it.
Therefore, to get the last page's next page, which is NULL, we had to
use page flag PG_Private_2 to identify it.

But now, we use page->freelist to link all of the pages in zspage and
init the page->freelist as NULL for last page, so no need to use
PG_Private_2 anymore.

This remove redundant SetPagePrivate2 in create_page_chain and
ClearPagePrivate2 in reset_page().  Save a few cycles for migration of
zsmalloc page :)

Link: http://lkml.kernel.org/r/1487076509-49270-1-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Vinayak Menon
e1587a4945 mm: vmpressure: fix sending wrong events on underflow
At the end of a window period, if the reclaimed pages is greater than
scanned, an unsigned underflow can result in a huge pressure value and
thus a critical event.  Reclaimed pages is found to go higher than
scanned because of the addition of reclaimed slab pages to reclaimed in
shrink_node without a corresponding increment to scanned pages.

Minchan Kim mentioned that this can also happen in the case of a THP
page where the scanned is 1 and reclaimed could be 512.

Link: http://lkml.kernel.org/r/1486641577-11685-1-git-send-email-vinmenon@codeaurora.org
Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Shiraz Hashim <shashim@codeaurora.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Hugh Dickins
3a4f8a0b3f mm: remove shmem_mapping() shmem_zero_setup() duplicates
Remove the prototypes for shmem_mapping() and shmem_zero_setup() from
linux/mm.h, since they are already provided in linux/shmem_fs.h.  But
shmem_fs.h must then provide the inline stub for shmem_mapping() when
CONFIG_SHMEM is not set, and a few more cfiles now need to #include it.

Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1702081658250.1549@eggly.anvils
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Gavin Shan
e02dc017c3 mm/page_alloc: fix nodes for reclaim in fast path
When @node_reclaim_node isn't 0, the page allocator tries to reclaim
pages if the amount of free memory in the zones are below the low
watermark.  On Power platform, none of NUMA nodes are scanned for page
reclaim because no nodes match the condition in zone_allows_reclaim().
On Power platform, RECLAIM_DISTANCE is set to 10 which is the distance
of Node-A to Node-A.  So the preferred node even won't be scanned for
page reclaim.

   __alloc_pages_nodemask()
   get_page_from_freelist()
      zone_allows_reclaim()

Anton proposed the test code as below:

   # cat alloc.c
      :
   int main(int argc, char *argv[])
   {
	void *p;
	unsigned long size;
	unsigned long start, end;

	start = time(NULL);
	size = strtoul(argv[1], NULL, 0);
	printf("To allocate %ldGB memory\n", size);

	size <<= 30;
	p = malloc(size);
	assert(p);
	memset(p, 0, size);

	end = time(NULL);
	printf("Used time: %ld seconds\n", end - start);
	sleep(3600);
	return 0;
   }

The system I use for testing has two NUMA nodes.  Both have 128GB
memory.  In below scnario, the page caches on node#0 should be reclaimed
when it encounters pressure to accommodate request of allocation.

   # echo 2 > /proc/sys/vm/zone_reclaim_mode; \
     sync; \
     echo 3 > /proc/sys/vm/drop_caches; \
   # taskset -c 0 cat file.32G > /dev/null; \
     grep FilePages /sys/devices/system/node/node0/meminfo
     Node 0 FilePages:       33619712 kB
   # taskset -c 0 ./alloc 128
   # grep FilePages /sys/devices/system/node/node0/meminfo
     Node 0 FilePages:       33619840 kB
   # grep MemFree /sys/devices/system/node/node0/meminfo
     Node 0 MemFree:          186816 kB

With the patch applied, the pagecache on node-0 is reclaimed when its
free memory is running out.  It's the expected behaviour.

   # echo 2 > /proc/sys/vm/zone_reclaim_mode; \
     sync; \
     echo 3 > /proc/sys/vm/drop_caches
   # taskset -c 0 cat file.32G > /dev/null; \
     grep FilePages /sys/devices/system/node/node0/meminfo
     Node 0 FilePages:       33605568 kB
   # taskset -c 0 ./alloc 128
   # grep FilePages /sys/devices/system/node/node0/meminfo
     Node 0 FilePages:        1379520 kB
   # grep MemFree /sys/devices/system/node/node0/meminfo
     Node 0 MemFree:           317120 kB

Fixes: 5f7a75acdb ("mm: page_alloc: do not cache reclaim distances")
Link: http://lkml.kernel.org/r/1486532455-29613-1-git-send-email-gwshan@linux.vnet.ibm.com
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: <stable@vger.kernel.org>	[3.16+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
zhong jiang
d6d8c8a482 mm/memory_hotplug.c: fix overflow in test_pages_in_a_zone()
When mainline introduced commit a96dfddbcc ("base/memory, hotplug: fix
a kernel oops in show_valid_zones()"), it obtained the valid start and
end pfn from the given pfn range.  The valid start pfn can fix the
actual issue, but it introduced another issue.  The valid end pfn will
may exceed the given end_pfn.

Although the incorrect overflow will not result in actual problem at
present, but I think it need to be fixed.

[toshi.kani@hpe.com: remove assumption that end_pfn is aligned by MAX_ORDER_NR_PAGES]
Fixes: a96dfddbcc ("base/memory, hotplug: fix a kernel oops in show_valid_zones()")
Link: http://lkml.kernel.org/r/1486467299-22648-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Steven Rostedt (VMware)
517663edd6 mm/page-writeback.c: place "not" inside of unlikely() statement in wb_domain_writeout_inc()
The likely/unlikely profiler noticed that the unlikely statement in
wb_domain_writeout_inc() is constantly wrong.  This is due to the "not"
(!) being outside the unlikely statement.  It is likely that
dom->period_time will be set, but unlikely that it wont be.  Move the
not into the unlikely statement.

Link: http://lkml.kernel.org/r/20170206120035.3c2e2b91@gandalf.local.home
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Aneesh Kumar K.V
595cd8f256 mm/ksm: handle protnone saved writes when making page write protect
Without this KSM will consider the page write protected, but a numa
fault can later mark the page writable.  This can result in memory
corruption.

Link: http://lkml.kernel.org/r/1487498625-10891-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Aneesh Kumar K.V
288bc54949 mm/autonuma: let architecture override how the write bit should be stashed in a protnone pte.
Patch series "Numabalancing preserve write fix", v2.

This patch series address an issue w.r.t THP migration and autonuma
preserve write feature.  migrate_misplaced_transhuge_page() cannot deal
with concurrent modification of the page.  It does a page copy without
following the migration pte sequence.  IIUC, this was done to keep the
migration simpler and at the time of implemenation we didn't had THP
page cache which would have required a more elaborate migration scheme.
That means thp autonuma migration expect the protnone with saved write
to be done such that both kernel and user cannot update the page
content.  This patch series enables archs like ppc64 to do that.  We are
good with the hash translation mode with the current code, because we
never create a hardware page table entry for a protnone pte.

This patch (of 2):

Autonuma preserves the write permission across numa fault to avoid
taking a writefault after a numa fault (Commit: b191f9b106 " mm: numa:
preserve PTE write permissions across a NUMA hinting fault").
Architecture can implement protnone in different ways and some may
choose to implement that by clearing Read/ Write/Exec bit of pte.
Setting the write bit on such pte can result in wrong behaviour.  Fix
this up by allowing arch to override how to save the write bit on a
protnone pte.

[aneesh.kumar@linux.vnet.ibm.com: don't mark pte saved write in case of dirty_accountable]
  Link: http://lkml.kernel.org/r/1487942884-16517-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com
[aneesh.kumar@linux.vnet.ibm.com: v3]
  Link: http://lkml.kernel.org/r/1487498625-10891-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1487050314-3892-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Michael Neuling <mikey@neuling.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Aneesh Kumar K.V
cee216a696 mm/autonuma: don't use set_pte_at when updating protnone ptes
Architectures like ppc64, use privilege access bit to mark pte non
accessible.  This implies that kernel can do a copy_to_user to an
address marked for numa fault.  This also implies that there can be a
parallel hardware update for the pte.  set_pte_at cannot be used in such
scenarios.  Hence switch the pte update to use ptep_get_and_clear and
set_pte_at combination.

[akpm@linux-foundation.org: remove unwanted ppc change, per Aneesh]
Link: http://lkml.kernel.org/r/1486400776-28114-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00
Steven Rostedt (VMware)
3f472cc978 mm/shmem.c: fix unlikely() test of info->seals to test only for WRITE and GROW
Running my likely/unlikely profiler, I discovered that the test in
shmem_write_begin() that tests for info->seals as unlikely, is always
incorrect.  This is because shmem_get_inode() sets info->seals to have
F_SEAL_SEAL set by default, and it is unlikely to be cleared when
shmem_write_begin() is called.  Thus, the if statement is very likely.

But as the if statement block only cares about F_SEAL_WRITE and
F_SEAL_GROW, change the test to only test those two bits.

Link: http://lkml.kernel.org/r/20170203105656.7aec6237@gandalf.local.home
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-24 17:46:56 -08:00