Commit Graph

19252 Commits

Author SHA1 Message Date
Mel Gorman
71e2d666ef mm/huge_memory: do not clobber swp_entry_t during THP split
The following has been observed when running stressng mmap since commit
b653db7735 ("mm: Clear page->private when splitting or migrating a page")

   watchdog: BUG: soft lockup - CPU#75 stuck for 26s! [stress-ng:9546]
   CPU: 75 PID: 9546 Comm: stress-ng Tainted: G            E      6.0.0-revert-b653db77-fix+ #29 0357d79b60fb09775f678e4f3f64ef0579ad1374
   Hardware name: SGI.COM C2112-4GP3/X10DRT-P-Series, BIOS 2.0a 05/09/2016
   RIP: 0010:xas_descend+0x28/0x80
   Code: cc cc 0f b6 0e 48 8b 57 08 48 d3 ea 83 e2 3f 89 d0 48 83 c0 04 48 8b 44 c6 08 48 89 77 18 48 89 c1 83 e1 03 48 83 f9 02 75 08 <48> 3d fd 00 00 00 76 08 88 57 12 c3 cc cc cc cc 48 c1 e8 02 89 c2
   RSP: 0018:ffffbbf02a2236a8 EFLAGS: 00000246
   RAX: ffff9cab7d6a0002 RBX: ffffe04b0af88040 RCX: 0000000000000002
   RDX: 0000000000000030 RSI: ffff9cab60509b60 RDI: ffffbbf02a2236c0
   RBP: 0000000000000000 R08: ffff9cab60509b60 R09: ffffbbf02a2236c0
   R10: 0000000000000001 R11: ffffbbf02a223698 R12: 0000000000000000
   R13: ffff9cab4e28da80 R14: 0000000000039c01 R15: ffff9cab4e28da88
   FS:  00007fab89b85e40(0000) GS:ffff9cea3fcc0000(0000) knlGS:0000000000000000
   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   CR2: 00007fab84e00000 CR3: 00000040b73a4003 CR4: 00000000003706e0
   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   Call Trace:
    <TASK>
    xas_load+0x3a/0x50
    __filemap_get_folio+0x80/0x370
    ? put_swap_page+0x163/0x360
    pagecache_get_page+0x13/0x90
    __try_to_reclaim_swap+0x50/0x190
    scan_swap_map_slots+0x31e/0x670
    get_swap_pages+0x226/0x3c0
    folio_alloc_swap+0x1cc/0x240
    add_to_swap+0x14/0x70
    shrink_page_list+0x968/0xbc0
    reclaim_page_list+0x70/0xf0
    reclaim_pages+0xdd/0x120
    madvise_cold_or_pageout_pte_range+0x814/0xf30
    walk_pgd_range+0x637/0xa30
    __walk_page_range+0x142/0x170
    walk_page_range+0x146/0x170
    madvise_pageout+0xb7/0x280
    ? asm_common_interrupt+0x22/0x40
    madvise_vma_behavior+0x3b7/0xac0
    ? find_vma+0x4a/0x70
    ? find_vma+0x64/0x70
    ? madvise_vma_anon_name+0x40/0x40
    madvise_walk_vmas+0xa6/0x130
    do_madvise+0x2f4/0x360
    __x64_sys_madvise+0x26/0x30
    do_syscall_64+0x5b/0x80
    ? do_syscall_64+0x67/0x80
    ? syscall_exit_to_user_mode+0x17/0x40
    ? do_syscall_64+0x67/0x80
    ? syscall_exit_to_user_mode+0x17/0x40
    ? do_syscall_64+0x67/0x80
    ? do_syscall_64+0x67/0x80
    ? common_interrupt+0x8b/0xa0
    entry_SYSCALL_64_after_hwframe+0x63/0xcd

The problem can be reproduced with the mmtests config
config-workload-stressng-mmap.  It does not always happen and when it
triggers is variable but it has happened on multiple machines.

The intent of commit b653db7735 patch was to avoid the case where
PG_private is clear but folio->private is not-NULL.  However, THP tail
pages uses page->private for "swp_entry_t if folio_test_swapcache()" as
stated in the documentation for struct folio.  This patch only clobbers
page->private for tail pages if the head page was not in swapcache and
warns once if page->private had an unexpected value.

Link: https://lkml.kernel.org/r/20221019134156.zjyyn5aownakvztf@techsingularity.net
Fixes: b653db7735 ("mm: Clear page->private when splitting or migrating a page")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Brian Foster <bfoster@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-20 21:27:24 -07:00
Mike Kravetz
612b8a3170 hugetlb: fix memory leak associated with vma_lock structure
The hugetlb vma_lock structure hangs off the vm_private_data pointer of
sharable hugetlb vmas.  The structure is vma specific and can not be
shared between vmas.  At fork and various other times, vmas are duplicated
via vm_area_dup().  When this happens, the pointer in the newly created
vma must be cleared and the structure reallocated.  Two hugetlb specific
routines deal with this hugetlb_dup_vma_private and hugetlb_vm_op_open. 
Both routines are called for newly created vmas.  hugetlb_dup_vma_private
would always clear the pointer and hugetlb_vm_op_open would allocate the
new vms_lock structure.  This did not work in the case of this calling
sequence pointed out in [1].

  move_vma
    copy_vma
      new_vma = vm_area_dup(vma);
      new_vma->vm_ops->open(new_vma); --> new_vma has its own vma lock.
    is_vm_hugetlb_page(vma)
      clear_vma_resv_huge_pages
        hugetlb_dup_vma_private --> vma->vm_private_data is set to NULL

When clearing hugetlb_dup_vma_private we actually leak the associated
vma_lock structure.

The vma_lock structure contains a pointer to the associated vma.  This
information can be used in hugetlb_dup_vma_private and hugetlb_vm_op_open
to ensure we only clear the vm_private_data of newly created (copied)
vmas.  In such cases, the vma->vma_lock->vma field will not point to the
vma.

Update hugetlb_dup_vma_private and hugetlb_vm_op_open to not clear
vm_private_data if vma->vma_lock->vma == vma.  Also, log a warning if
hugetlb_vm_op_open ever encounters the case where vma_lock has already
been correctly allocated for the vma.

[1] https://lore.kernel.org/linux-mm/5154292a-4c55-28cd-0935-82441e512fc3@huawei.com/

Link: https://lkml.kernel.org/r/20221019201957.34607-1-mike.kravetz@oracle.com
Fixes: 131a79b474 ("hugetlb: fix vma lock handling during split vma and range unmapping")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-20 21:27:23 -07:00
Liam R. Howlett
df48a5f7a3 mm/page_alloc: reduce potential fragmentation in make_alloc_exact()
Try to avoid using the left over split page on the next request for a page
by calling __free_pages_ok() with FPI_TO_TAIL.  This increases the
potential of defragmenting memory when it's used for a short period of
time.

Link: https://lkml.kernel.org/r/20220531185626.yvlmymbxyoe5vags@revolver
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-20 21:27:23 -07:00
Rik van Riel
12df140f0b mm,hugetlb: take hugetlb_lock before decrementing h->resv_huge_pages
The h->*_huge_pages counters are protected by the hugetlb_lock, but
alloc_huge_page has a corner case where it can decrement the counter
outside of the lock.

This could lead to a corrupted value of h->resv_huge_pages, which we have
observed on our systems.

Take the hugetlb_lock before decrementing h->resv_huge_pages to avoid a
potential race.

Link: https://lkml.kernel.org/r/20221017202505.0e6a4fcd@imladris.surriel.com
Fixes: a88c769548 ("mm: hugetlb: fix hugepage memory leak caused by wrong reserve count")
Signed-off-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Glen McCready <gkmccready@meta.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-20 21:27:23 -07:00
Liam Howlett
a57b70519d mm/mmap: fix MAP_FIXED address return on VMA merge
mmap should return the start address of newly mapped area when successful.
On a successful merge of a VMA, the return address was changed and thus
was violating that expectation from userspace.

This is a restoration of functionality provided by 309d08d9b3
(mm/mmap.c: fix mmap return value when vma is merged after call_mmap()). 
For completeness of fixing MAP_FIXED, implement the comments from the
previous discussion to never update the address and fail if the address
changes.  Leaving the error as a WARN_ON() to avoid crashing the kernel.

Link: https://lkml.kernel.org/r/20221018191613.4133459-1-Liam.Howlett@oracle.com
Link: https://lore.kernel.org/all/Y06yk66SKxlrwwfb@lakrids/
Link: https://lore.kernel.org/all/20201203085350.22624-1-liuzixian4@huawei.com/
Fixes: 4dd1b84140 ("mm/mmap: use advanced maple tree API for mmap_region()")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Mark Rutland <mark.rutland@arm.com>
Cc: Liu Zixian <liuzixian4@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-20 21:27:23 -07:00
Andrew Morton
1cd916d034 mm/mmap.c: __vma_adjust(): suppress uninitialized var warning
The code is OK, but it fools gcc.

mm/mmap.c:802 __vma_adjust() error: uninitialized symbol 'next_next'.

Fixes: 524e00b36e ("mm: remove rb tree.")
Reported-by: kernel test robot <lkp@intel.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-20 21:27:23 -07:00
Mike Kravetz
5789151e48 mm/mmap: undo ->mmap() when mas_preallocate() fails
A memory leak in hugetlb_reserve_pages was reported in [1].  The root
cause was traced to an error path in mmap_region when mas_preallocate()
fails.  In this case, the vma is freed after a successful call to
filesystem specific mmap.  The hugetlbfs mmap routine may allocate data
structures pointed to by m_private_data.  These need to be cleaned up by
the hugetlb vm_ops->close() routine.

The same issue was addressed by commit deb0f65628 ("mm/mmap: undo
->mmap() when arch_validate_flags() fails") for the arch_validate_flags()
test.  Go to the same close_and_free_vma label if mas_preallocate() fails.

[1] https://lore.kernel.org/linux-mm/CAKXUXMxf7OiCwbxib7MwfR4M1b5+b3cNTU7n5NV9Zm4967=FPQ@mail.gmail.com/

Link: https://lkml.kernel.org/r/20221018024945.415036-1-mike.kravetz@oracle.com
Fixes: d4af56c5c7 ("mm: start tracking VMAs with maple tree")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-20 21:27:22 -07:00
Alexey Romanov
4249a05ff6 zsmalloc: zs_destroy_pool: add size_class NULL check
Inside the zs_destroy_pool() function, there can still be NULL size_class
pointers: if when the next size_class is allocated, inside
zs_create_pool() function, kzalloc will return NULL and handling the error
condition, zs_create_pool() will call zs_destroy_pool().

Link: https://lkml.kernel.org/r/20221013112825.61869-1-avromanov@sberdevices.ru
Fixes: f24263a5a0 ("zsmalloc: remove unnecessary size_class NULL check")
Signed-off-by: Alexey Romanov <avromanov@sberdevices.ru>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-20 21:27:21 -07:00
Liam Howlett
7329e3ebe3 mm/mempolicy: fix mbind_range() arguments to vma_merge()
Fuzzing produced an invalid argument to vma_merge() which was caught by
the newly added verification of the number of VMAs being removed on
process exit.  Analyzing the failure eventually resulted in finding an
issue with the search of a VMA that started at address 0, which caused an
underflow and thus the loss of many VMAs being tracked in the tree.  Fix
the underflow by changing the search of the maple tree to use the start
address directly.

Link: https://lkml.kernel.org/r/20221015021135.2816178-1-Liam.Howlett@oracle.com
Fixes: 66850be55e ("mm/mempolicy: use vma iterator & maple state instead of vma linked list")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
  Link: https://lore.kernel.org/r/202210052318.5ad10912-oliver.sang@intel.com
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-20 21:27:21 -07:00
Linus Torvalds
f1947d7c8a Random number generator fixes for Linux 6.1-rc1.
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Merge tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull more random number generator updates from Jason Donenfeld:
 "This time with some large scale treewide cleanups.

  The intent of this pull is to clean up the way callers fetch random
  integers. The current rules for doing this right are:

   - If you want a secure or an insecure random u64, use get_random_u64()

   - If you want a secure or an insecure random u32, use get_random_u32()

     The old function prandom_u32() has been deprecated for a while
     now and is just a wrapper around get_random_u32(). Same for
     get_random_int().

   - If you want a secure or an insecure random u16, use get_random_u16()

   - If you want a secure or an insecure random u8, use get_random_u8()

   - If you want secure or insecure random bytes, use get_random_bytes().

     The old function prandom_bytes() has been deprecated for a while
     now and has long been a wrapper around get_random_bytes()

   - If you want a non-uniform random u32, u16, or u8 bounded by a
     certain open interval maximum, use prandom_u32_max()

     I say "non-uniform", because it doesn't do any rejection sampling
     or divisions. Hence, it stays within the prandom_*() namespace, not
     the get_random_*() namespace.

     I'm currently investigating a "uniform" function for 6.2. We'll see
     what comes of that.

  By applying these rules uniformly, we get several benefits:

   - By using prandom_u32_max() with an upper-bound that the compiler
     can prove at compile-time is ≤65536 or ≤256, internally
     get_random_u16() or get_random_u8() is used, which wastes fewer
     batched random bytes, and hence has higher throughput.

   - By using prandom_u32_max() instead of %, when the upper-bound is
     not a constant, division is still avoided, because
     prandom_u32_max() uses a faster multiplication-based trick instead.

   - By using get_random_u16() or get_random_u8() in cases where the
     return value is intended to indeed be a u16 or a u8, we waste fewer
     batched random bytes, and hence have higher throughput.

  This series was originally done by hand while I was on an airplane
  without Internet. Later, Kees and I worked on retroactively figuring
  out what could be done with Coccinelle and what had to be done
  manually, and then we split things up based on that.

  So while this touches a lot of files, the actual amount of code that's
  hand fiddled is comfortably small"

* tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  prandom: remove unused functions
  treewide: use get_random_bytes() when possible
  treewide: use get_random_u32() when possible
  treewide: use get_random_{u8,u16}() when possible, part 2
  treewide: use get_random_{u8,u16}() when possible, part 1
  treewide: use prandom_u32_max() when possible, part 2
  treewide: use prandom_u32_max() when possible, part 1
2022-10-16 15:27:07 -07:00
Linus Torvalds
1501278bb7 slab hotfix for 6.1-rc1
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Merge tag 'slab-for-6.1-rc1-hotfix' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab hotfix from Vlastimil Babka:
 "A single fix for the common-kmalloc series, for warnings on mips and
  sparc64 reported by Guenter Roeck"

* tag 'slab-for-6.1-rc1-hotfix' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
  mm/slab: use kmalloc_node() for off slab freelist_idx_t array allocation
2022-10-15 17:05:07 -07:00
Hyeonggon Yoo
e36ce448a0 mm/slab: use kmalloc_node() for off slab freelist_idx_t array allocation
After commit d6a71648db ("mm/slab: kmalloc: pass requests larger than
order-1 page to page allocator"), SLAB passes large ( > PAGE_SIZE * 2)
requests to buddy like SLUB does.

SLAB has been using kmalloc caches to allocate freelist_idx_t array for
off slab caches. But after the commit, freelist_size can be bigger than
KMALLOC_MAX_CACHE_SIZE.

Instead of using pointer to kmalloc cache, use kmalloc_node() and only
check if the kmalloc cache is off slab during calculate_slab_order().
If freelist_size > KMALLOC_MAX_CACHE_SIZE, no looping condition happens
as it allocates freelist_idx_t array directly from buddy.

Link: https://lore.kernel.org/all/20221014205818.GA1428667@roeck-us.net/
Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Fixes: d6a71648db ("mm/slab: kmalloc: pass requests larger than order-1 page to page allocator")
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
2022-10-15 21:42:05 +02:00
Linus Torvalds
5e714bf171 - Alistair Popple has a series which addresses a race which causes page
refcounting errors in ZONE_DEVICE pages.
 
 - Peter Xu fixes some userfaultfd test harness instability.
 
 - Various other patches in MM, mainly fixes.
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Merge tag 'mm-stable-2022-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull more MM updates from Andrew Morton:

 - fix a race which causes page refcounting errors in ZONE_DEVICE pages
   (Alistair Popple)

 - fix userfaultfd test harness instability (Peter Xu)

 - various other patches in MM, mainly fixes

* tag 'mm-stable-2022-10-13' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (29 commits)
  highmem: fix kmap_to_page() for kmap_local_page() addresses
  mm/page_alloc: fix incorrect PGFREE and PGALLOC for high-order page
  mm/selftest: uffd: explain the write missing fault check
  mm/hugetlb: use hugetlb_pte_stable in migration race check
  mm/hugetlb: fix race condition of uffd missing/minor handling
  zram: always expose rw_page
  LoongArch: update local TLB if PTE entry exists
  mm: use update_mmu_tlb() on the second thread
  kasan: fix array-bounds warnings in tests
  hmm-tests: add test for migrate_device_range()
  nouveau/dmem: evict device private memory during release
  nouveau/dmem: refactor nouveau_dmem_fault_copy_one()
  mm/migrate_device.c: add migrate_device_range()
  mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()
  mm/memremap.c: take a pgmap reference on page allocation
  mm: free device private pages have zero refcount
  mm/memory.c: fix race when faulting a device private page
  mm/damon: use damon_sz_region() in appropriate place
  mm/damon: move sz_damon_region to damon_sz_region
  lib/test_meminit: add checks for the allocation functions
  ...
2022-10-14 12:28:43 -07:00
Ira Weiny
ef6e06b2ef highmem: fix kmap_to_page() for kmap_local_page() addresses
kmap_to_page() is used to get the page for a virtual address which may
be kmap'ed.  Unfortunately, kmap_local_page() stores mappings in a
thread local array separate from kmap().  These mappings were not
checked by the call.

Check the kmap_local_page() mappings and return the page if found.

Because it is intended to remove kmap_to_page() add a warn on once to
the kmap checks to flag potential issues early.

NOTE Due to 32bit x86 use of kmap local in iomap atmoic, KMAP_LOCAL does
not require HIGHMEM to be set.  Therefore the support calls required a
new KMAP_LOCAL section to fix 0day build errors.

[akpm@linux-foundation.org: fix warning]
Link: https://lkml.kernel.org/r/20221006040555.1502679-1-ira.weiny@intel.com
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Reported-by: kernel test robot <lkp@intel.com>
Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:51 -07:00
Yafang Shao
15cd90049d mm/page_alloc: fix incorrect PGFREE and PGALLOC for high-order page
PGFREE and PGALLOC represent the number of freed and allocated pages.  So
the page order must be considered.

Link: https://lkml.kernel.org/r/20221006101540.40686-1-laoar.shao@gmail.com
Fixes: 44042b4498 ("mm/page_alloc: allow high-order pages to be stored on the per-cpu lists")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:51 -07:00
Peter Xu
f9bf6c03ec mm/hugetlb: use hugetlb_pte_stable in migration race check
After hugetlb_pte_stable() introduced, we can also rewrite the migration
race condition against page allocation to use the new helper too.

Link: https://lkml.kernel.org/r/20221004193400.110155-3-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:50 -07:00
Peter Xu
2ea7ff1e39 mm/hugetlb: fix race condition of uffd missing/minor handling
Patch series "mm/hugetlb: Fix selftest failures with write check", v3.

Currently akpm mm-unstable fails with uffd hugetlb private mapping test
randomly on a write check.

The initial bisection of that points to the recent pmd unshare series, but
it turns out there's no direction relationship with the series but only
some timing change caused the race to start trigger.

The race should be fixed in patch 1.  Patch 2 is a trivial cleanup on the
similar race with hugetlb migrations, patch 3 comment on the write check
so when anyone read it again it'll be clear why it's there.


This patch (of 3):

After the recent rework patchset of hugetlb locking on pmd sharing,
kselftest for userfaultfd sometimes fails on hugetlb private tests with
unexpected write fault checks.

It turns out there's nothing wrong within the locking series regarding
this matter, but it could have changed the timing of threads so it can
trigger an old bug.

The real bug is when we call hugetlb_no_page() we're not with the pgtable
lock.  It means we're reading the pte values lockless.  It's perfectly
fine in most cases because before we do normal page allocations we'll take
the lock and check pte_same() again.  However before that, there are
actually two paths on userfaultfd missing/minor handling that may directly
move on with the fault process without checking the pte values.

It means for these two paths we may be generating an uffd message based on
an unstable pte, while an unstable pte can legally be anything as long as
the modifier holds the pgtable lock.

One example, which is also what happened in the failing kselftest and
caused the test failure, is that for private mappings wr-protection
changes can happen on one page.  While hugetlb_change_protection()
generally requires pte being cleared before being changed, then there can
be a race condition like:

        thread 1                              thread 2
        --------                              --------

      UFFDIO_WRITEPROTECT                     hugetlb_fault
        hugetlb_change_protection
          pgtable_lock()
          huge_ptep_modify_prot_start
                                              pte==NULL
                                              hugetlb_no_page
                                                generate uffd missing event
                                                even if page existed!!
          huge_ptep_modify_prot_commit
          pgtable_unlock()

Fix this by rechecking the pte after pgtable lock for both userfaultfd
missing & minor fault paths.

This bug should have been around starting from uffd hugetlb introduced, so
attaching a Fixes to the commit.  Also attach another Fixes to the minor
support commit for easier tracking.

Note that userfaultfd is actually fine with false positives (e.g.  caused
by pte changed), but not wrong logical events (e.g.  caused by reading a
pte during changing).  The latter can confuse the userspace, so the
strictness is very much preferred.  E.g., MISSING event should never
happen on the page after UFFDIO_COPY has correctly installed the page and
returned.

Link: https://lkml.kernel.org/r/20221004193400.110155-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20221004193400.110155-2-peterx@redhat.com
Fixes: 1a1aad8a9b ("userfaultfd: hugetlbfs: add userfaultfd hugetlb hook")
Fixes: 7677f7fd8b ("userfaultfd: add minor fault registration mode")
Signed-off-by: Peter Xu <peterx@redhat.com>
Co-developed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:50 -07:00
Qi Zheng
bce8cb3c04 mm: use update_mmu_tlb() on the second thread
As message in commit 7df6769743 ("mm/memory.c: Update local TLB if PTE
entry exists") said, we should update local TLB only on the second thread.
So in the do_anonymous_page() here, we should use update_mmu_tlb()
instead of update_mmu_cache() on the second thread.

As David pointed out, this is a performance improvement, not a
correctness fix.

Link: https://lkml.kernel.org/r/20220929112318.32393-2-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: Chris Zankel <chris@zankel.net>
Cc: Huacai Chen <chenhuacai@loongson.cn>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:50 -07:00
Andrey Konovalov
d6e5040bd8 kasan: fix array-bounds warnings in tests
GCC's -Warray-bounds option detects out-of-bounds accesses to
statically-sized allocations in krealloc out-of-bounds tests.

Use OPTIMIZER_HIDE_VAR to suppress the warning.

Also change kmalloc_memmove_invalid_size to use OPTIMIZER_HIDE_VAR
instead of a volatile variable.

Link: https://lkml.kernel.org/r/e94399242d32e00bba6fd0d9ec4c897f188128e8.1664215688.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:50 -07:00
Alistair Popple
e778406b40 mm/migrate_device.c: add migrate_device_range()
Device drivers can use the migrate_vma family of functions to migrate
existing private anonymous mappings to device private pages.  These pages
are backed by memory on the device with drivers being responsible for
copying data to and from device memory.

Device private pages are freed via the pgmap->page_free() callback when
they are unmapped and their refcount drops to zero.  Alternatively they
may be freed indirectly via migration back to CPU memory in response to a
pgmap->migrate_to_ram() callback called whenever the CPU accesses an
address mapped to a device private page.

In other words drivers cannot control the lifetime of data allocated on
the devices and must wait until these pages are freed from userspace. 
This causes issues when memory needs to reclaimed on the device, either
because the device is going away due to a ->release() callback or because
another user needs to use the memory.

Drivers could use the existing migrate_vma functions to migrate data off
the device.  However this would require them to track the mappings of each
page which is both complicated and not always possible.  Instead drivers
need to be able to migrate device pages directly so they can free up
device memory.

To allow that this patch introduces the migrate_device family of functions
which are functionally similar to migrate_vma but which skips the initial
lookup based on mapping.

Link: https://lkml.kernel.org/r/868116aab70b0c8ee467d62498bb2cf0ef907295.1664366292.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:49 -07:00
Alistair Popple
241f688596 mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()
migrate_device_coherent_page() reuses the existing migrate_vma family of
functions to migrate a specific page without providing a valid mapping or
vma.  This looks a bit odd because it means we are calling migrate_vma_*()
without setting a valid vma, however it was considered acceptable at the
time because the details were internal to migrate_device.c and there was
only a single user.

One of the reasons the details could be kept internal was that this was
strictly for migrating device coherent memory.  Such memory can be copied
directly by the CPU without intervention from a driver.  However this
isn't true for device private memory, and a future change requires similar
functionality for device private memory.  So refactor the code into
something more sensible for migrating device memory without a vma.

Link: https://lkml.kernel.org/r/c7b2ff84e9b33d022cf4a40f87d051f281a16d8f.1664366292.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:49 -07:00
Alistair Popple
0dc45ca1ce mm/memremap.c: take a pgmap reference on page allocation
ZONE_DEVICE pages have a struct dev_pagemap which is allocated by a
driver.  When the struct page is first allocated by the kernel in
memremap_pages() a reference is taken on the associated pagemap to ensure
it is not freed prior to the pages being freed.

Prior to 27674ef6c7 ("mm: remove the extra ZONE_DEVICE struct page
refcount") pages were considered free and returned to the driver when the
reference count dropped to one.  However the pagemap reference was not
dropped until the page reference count hit zero.  This would occur as part
of the final put_page() in memunmap_pages() which would wait for all pages
to be freed prior to returning.

When the extra refcount was removed the pagemap reference was no longer
being dropped in put_page().  Instead memunmap_pages() was changed to
explicitly drop the pagemap references.  This means that memunmap_pages()
can complete even though pages are still mapped by the kernel which can
lead to kernel crashes, particularly if a driver frees the pagemap.

To fix this drivers should take a pagemap reference when allocating the
page.  This reference can then be returned when the page is freed.

Link: https://lkml.kernel.org/r/12d155ec727935ebfbb4d639a03ab374917ea51b.1664366292.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Fixes: 27674ef6c7 ("mm: remove the extra ZONE_DEVICE struct page refcount")
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>

Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:49 -07:00
Alistair Popple
ef23345089 mm: free device private pages have zero refcount
Since 27674ef6c7 ("mm: remove the extra ZONE_DEVICE struct page
refcount") device private pages have no longer had an extra reference
count when the page is in use.  However before handing them back to the
owning device driver we add an extra reference count such that free pages
have a reference count of one.

This makes it difficult to tell if a page is free or not because both free
and in use pages will have a non-zero refcount.  Instead we should return
pages to the drivers page allocator with a zero reference count.  Kernel
code can then safely use kernel functions such as get_page_unless_zero().

Link: https://lkml.kernel.org/r/cf70cf6f8c0bdb8aaebdbfb0d790aea4c683c3c6.1664366292.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:49 -07:00
Alistair Popple
16ce101db8 mm/memory.c: fix race when faulting a device private page
Patch series "Fix several device private page reference counting issues",
v2

This series aims to fix a number of page reference counting issues in
drivers dealing with device private ZONE_DEVICE pages.  These result in
use-after-free type bugs, either from accessing a struct page which no
longer exists because it has been removed or accessing fields within the
struct page which are no longer valid because the page has been freed.

During normal usage it is unlikely these will cause any problems.  However
without these fixes it is possible to crash the kernel from userspace. 
These crashes can be triggered either by unloading the kernel module or
unbinding the device from the driver prior to a userspace task exiting. 
In modules such as Nouveau it is also possible to trigger some of these
issues by explicitly closing the device file-descriptor prior to the task
exiting and then accessing device private memory.

This involves some minor changes to both PowerPC and AMD GPU code. 
Unfortunately I lack hardware to test either of those so any help there
would be appreciated.  The changes mimic what is done in for both Nouveau
and hmm-tests though so I doubt they will cause problems.


This patch (of 8):

When the CPU tries to access a device private page the migrate_to_ram()
callback associated with the pgmap for the page is called.  However no
reference is taken on the faulting page.  Therefore a concurrent migration
of the device private page can free the page and possibly the underlying
pgmap.  This results in a race which can crash the kernel due to the
migrate_to_ram() function pointer becoming invalid.  It also means drivers
can't reliably read the zone_device_data field because the page may have
been freed with memunmap_pages().

Close the race by getting a reference on the page while holding the ptl to
ensure it has not been freed.  Unfortunately the elevated reference count
will cause the migration required to handle the fault to fail.  To avoid
this failure pass the faulting page into the migrate_vma functions so that
if an elevated reference count is found it can be checked to see if it's
expected or not.

[mpe@ellerman.id.au: fix build]
  Link: https://lkml.kernel.org/r/87fsgbf3gh.fsf@mpe.ellerman.id.au
Link: https://lkml.kernel.org/r/cover.60659b549d8509ddecafad4f498ee7f03bb23c69.1664366292.git-series.apopple@nvidia.com
Link: https://lkml.kernel.org/r/d3e813178a59e565e8d78d9b9a4e2562f6494f90.1664366292.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alex Sierra <alex.sierra@amd.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:49 -07:00
Xin Hao
ab63f63f38 mm/damon: use damon_sz_region() in appropriate place
In many places we can use damon_sz_region() to instead of "r->ar.end -
r->ar.start".

Link: https://lkml.kernel.org/r/20220927001946.85375-2-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:49 -07:00
Xin Hao
652e04464d mm/damon: move sz_damon_region to damon_sz_region
Rename sz_damon_region() to damon_sz_region(), and move it to
"include/linux/damon.h", because in many places, we can to use this func.

Link: https://lkml.kernel.org/r/20220927001946.85375-1-xhao@linux.alibaba.com
Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
Suggested-by: SeongJae Park <sj@kernel.org>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:49 -07:00
Alexander Potapenko
ac801e7e25 kmsan: unpoison @tlb in arch_tlb_gather_mmu()
This is an optimization to reduce stackdepot pressure.

struct mmu_gather contains 7 1-bit fields packed into a 32-bit unsigned
int value.  The remaining 25 bits remain uninitialized and are never used,
but KMSAN updates the origin for them in zap_pXX_range() in mm/memory.c,
thus creating very long origin chains.  This is technically correct, but
consumes too much memory.

Unpoisoning the whole structure will prevent creating such chains.

Link: https://lkml.kernel.org/r/20220905122452.2258262-20-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:48 -07:00
Carlos Llamas
deb0f65628 mm/mmap: undo ->mmap() when arch_validate_flags() fails
Commit c462ac288f ("mm: Introduce arch_validate_flags()") added a late
check in mmap_region() to let architectures validate vm_flags.  The check
needs to happen after calling ->mmap() as the flags can potentially be
modified during this callback.

If arch_validate_flags() check fails we unmap and free the vma.  However,
the error path fails to undo the ->mmap() call that previously succeeded
and depending on the specific ->mmap() implementation this translates to
reference increments, memory allocations and other operations what will
not be cleaned up.

There are several places (mainly device drivers) where this is an issue.
However, one specific example is bpf_map_mmap() which keeps count of the
mappings in map->writecnt.  The count is incremented on ->mmap() and then
decremented on vm_ops->close().  When arch_validate_flags() fails this
count is off since bpf_map_mmap_close() is never called.

One can reproduce this issue in arm64 devices with MTE support.  Here the
vm_flags are checked to only allow VM_MTE if VM_MTE_ALLOWED has been set
previously.  From userspace then is enough to pass the PROT_MTE flag to
mmap() syscall to trigger the arch_validate_flags() failure.

The following program reproduces this issue:

  #include <stdio.h>
  #include <unistd.h>
  #include <linux/unistd.h>
  #include <linux/bpf.h>
  #include <sys/mman.h>

  int main(void)
  {
	union bpf_attr attr = {
		.map_type = BPF_MAP_TYPE_ARRAY,
		.key_size = sizeof(int),
		.value_size = sizeof(long long),
		.max_entries = 256,
		.map_flags = BPF_F_MMAPABLE,
	};
	int fd;

	fd = syscall(__NR_bpf, BPF_MAP_CREATE, &attr, sizeof(attr));
	mmap(NULL, 4096, PROT_WRITE | PROT_MTE, MAP_SHARED, fd, 0);

	return 0;
  }

By manually adding some log statements to the vm_ops callbacks we can
confirm that when passing PROT_MTE to mmap() the map->writecnt is off upon
->release():

With PROT_MTE flag:
  root@debian:~# ./bpf-test
  [  111.263874] bpf_map_write_active_inc: map=9 writecnt=1
  [  111.288763] bpf_map_release: map=9 writecnt=1

Without PROT_MTE flag:
  root@debian:~# ./bpf-test
  [  157.816912] bpf_map_write_active_inc: map=10 writecnt=1
  [  157.830442] bpf_map_write_active_dec: map=10 writecnt=0
  [  157.832396] bpf_map_release: map=10 writecnt=0

This patch fixes the above issue by calling vm_ops->close() when the
arch_validate_flags() check fails, after this we can proceed to unmap and
free the vma on the error path.

Link: https://lkml.kernel.org/r/20220930003844.1210987-1-cmllamas@google.com
Fixes: c462ac288f ("mm: Introduce arch_validate_flags()")
Signed-off-by: Carlos Llamas <cmllamas@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Liam Howlett <liam.howlett@oracle.com>
Cc: Christian Brauner (Microsoft) <brauner@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>	[5.10+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 18:51:36 -07:00
Peter Xu
515778e2d7 mm/uffd: fix warning without PTE_MARKER_UFFD_WP compiled in
When PTE_MARKER_UFFD_WP not configured, it's still possible to reach pte
marker code and trigger an warning. Add a few CONFIG_PTE_MARKER_UFFD_WP
ifdefs to make sure the code won't be reached when not compiled in.

Link: https://lkml.kernel.org/r/YzeR+R6b4bwBlBHh@x1n
Fixes: b1f9e87686 ("mm/uffd: enable write protection for shmem & hugetlbfs")
Signed-off-by: Peter Xu <peterx@redhat.com>
Reported-by: <syzbot+2b9b4f0895be09a6dec3@syzkaller.appspotmail.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Edward Liaw <edliaw@google.com>
Cc: Liu Shixin <liushixin2@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 15:56:46 -07:00
Liam Howlett
28c5609fb2 mm/mmap: preallocate maple nodes for brk vma expansion
If the brk VMA is the last vma in a maple node and meets the rare criteria
that it can be expanded, then preallocation is necessary to avoid a
potential fs_reclaim circular lock issue on low resources.

At the same time use the actual vma start address (unaligned) when calling
vma_adjust_trans_huge().

Link: https://lkml.kernel.org/r/20221011160624.1253454-1-Liam.Howlett@oracle.com
Fixes: 2e7ce7d354 (mm/mmap: change do_brk_flags() to expand existing VMA and add do_brk_munmap())
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 15:56:46 -07:00
Liam Howlett
92b7399695 mmap: fix copy_vma() failure path
The anon vma was not unlinked and the file was not closed in the failure
path when the machine runs out of memory during the maple tree
modification.  This caused a memory leak of the anon vma chain and vma
since neither would be freed.

Link: https://lkml.kernel.org/r/20221011203621.1446507-1-Liam.Howlett@oracle.com
Fixes: 524e00b36e ("mm: remove rb tree")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 15:56:46 -07:00
Chuyi Zhou
7efc3b7261 mm/compaction: fix set skip in fast_find_migrateblock
When we successfully find a pageblock in fast_find_migrateblock(), the
block will be set skip-flag through set_pageblock_skip().  However, when
entering isolate_migratepages_block(), the whole pageblock will be skipped
due to the branch 'if (!valid_page && IS_ALIGNED(low_pfn,
pageblock_nr_pages))'.  Eventually we will goto isolate_abort and isolate
nothing.  That makes fast_find_migrateblock useless.

In this patch, when we find a suitable pageblock in
fast_find_migrateblock, we do noting but let isolate_migratepages_block to
set skip flag to the pageblock after scan it.  Normally, we would isolate
some pages from the fast-find block.

I use mmtest/thpscale-madvhugepage test it. Here is the result:
                            baseline               patch
Amean     fault-both-1      1331.66 (   0.00%)     1261.04 *   5.30%*
Amean     fault-both-3      1383.95 (   0.00%)     1191.69 *  13.89%*
Amean     fault-both-5      1568.13 (   0.00%)     1445.20 *   7.84%*
Amean     fault-both-7      1819.62 (   0.00%)     1555.13 *  14.54%*
Amean     fault-both-12     1106.96 (   0.00%)     1149.43 *  -3.84%*
Amean     fault-both-18     2196.93 (   0.00%)     1875.77 *  14.62%*
Amean     fault-both-24     2642.69 (   0.00%)     2671.21 *  -1.08%*
Amean     fault-both-30     2901.89 (   0.00%)     2857.32 *   1.54%*
Amean     fault-both-32     3747.00 (   0.00%)     3479.23 *   7.15%*

Link: https://lkml.kernel.org/r/20220713062009.597255-1-zhouchuyi@bytedance.com
Fixes: 70b44595ea ("mm, compaction: use free lists to quickly locate a migration source")
Signed-off-by: zhouchuyi <zhouchuyi@bytedance.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 15:56:45 -07:00
Andrew Morton
acfac37851 mm/hugetlb.c: make __hugetlb_vma_unlock_write_put() static
Reported-by: kernel test robot <lkp@intel.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-12 15:56:45 -07:00
Linus Torvalds
1440f57602 Five hotfixes - three for nilfs2, two for MM. For are cc:stable, one is
not.
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Merge tag 'mm-hotfixes-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc hotfixes from Andrew Morton:
 "Five hotfixes - three for nilfs2, two for MM. For are cc:stable, one
  is not"

* tag 'mm-hotfixes-stable-2022-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  nilfs2: fix leak of nilfs_root in case of writer thread creation failure
  nilfs2: fix NULL pointer dereference at nilfs_bmap_lookup_at_level()
  nilfs2: fix use-after-free bug of struct nilfs_root
  mm/damon/core: initialize damon_target->list in damon_new_target()
  mm/hugetlb: fix races when looking up a CONT-PTE/PMD size hugetlb page
2022-10-12 11:16:58 -07:00
SeongJae Park
b1f44cdaba mm/damon/core: initialize damon_target->list in damon_new_target()
'struct damon_target' creation function, 'damon_new_target()' is not
initializing its '->list' field, unlike other DAMON structs creator
functions such as 'damon_new_region()'.  Normal users of
'damon_new_target()' initializes the field by adding the target to DAMON
context's targets list, but some code could access the uninitialized
field.

This commit avoids the case by initializing the field in
'damon_new_target()'.

Link: https://lkml.kernel.org/r/20221002193130.8227-1-sj@kernel.org
Fixes: f23b8eee18 ("mm/damon/core: implement region-based sampling")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-11 19:05:44 -07:00
Baolin Wang
fac35ba763 mm/hugetlb: fix races when looking up a CONT-PTE/PMD size hugetlb page
On some architectures (like ARM64), it can support CONT-PTE/PMD size
hugetlb, which means it can support not only PMD/PUD size hugetlb (2M and
1G), but also CONT-PTE/PMD size(64K and 32M) if a 4K page size specified.

So when looking up a CONT-PTE size hugetlb page by follow_page(), it will
use pte_offset_map_lock() to get the pte entry lock for the CONT-PTE size
hugetlb in follow_page_pte().  However this pte entry lock is incorrect
for the CONT-PTE size hugetlb, since we should use huge_pte_lock() to get
the correct lock, which is mm->page_table_lock.

That means the pte entry of the CONT-PTE size hugetlb under current pte
lock is unstable in follow_page_pte(), we can continue to migrate or
poison the pte entry of the CONT-PTE size hugetlb, which can cause some
potential race issues, even though they are under the 'pte lock'.

For example, suppose thread A is trying to look up a CONT-PTE size hugetlb
page by move_pages() syscall under the lock, however antoher thread B can
migrate the CONT-PTE hugetlb page at the same time, which will cause
thread A to get an incorrect page, if thread A also wants to do page
migration, then data inconsistency error occurs.

Moreover we have the same issue for CONT-PMD size hugetlb in
follow_huge_pmd().

To fix above issues, rename the follow_huge_pmd() as follow_huge_pmd_pte()
to handle PMD and PTE level size hugetlb, which uses huge_pte_lock() to
get the correct pte entry lock to make the pte entry stable.

Mike said:

Support for CONT_PMD/_PTE was added with bb9dd3df8e ("arm64: hugetlb:
refactor find_num_contig()").  Patch series "Support for contiguous pte
hugepages", v4.  However, I do not believe these code paths were
executed until migration support was added with 5480280d3f ("arm64/mm:
enable HugeTLB migration for contiguous bit HugeTLB pages") I would go
with 5480280d3f for the Fixes: targe.

Link: https://lkml.kernel.org/r/635f43bdd85ac2615a58405da82b4d33c6e5eb05.1662017562.git.baolin.wang@linux.alibaba.com
Fixes: 5480280d3f ("arm64/mm: enable HugeTLB migration for contiguous bit HugeTLB pages")
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-11 19:05:44 -07:00
Jason A. Donenfeld
a251c17aa5 treewide: use get_random_u32() when possible
The prandom_u32() function has been a deprecated inline wrapper around
get_random_u32() for several releases now, and compiles down to the
exact same code. Replace the deprecated wrapper with a direct call to
the real function. The same also applies to get_random_int(), which is
just a wrapper around get_random_u32(). This was done as a basic find
and replace.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> # for sch_cake
Acked-by: Chuck Lever <chuck.lever@oracle.com> # for nfsd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> # for thunderbolt
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Acked-by: Helge Deller <deller@gmx.de> # for parisc
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-10-11 17:42:58 -06:00
Jason A. Donenfeld
81895a65ec treewide: use prandom_u32_max() when possible, part 1
Rather than incurring a division or requesting too many random bytes for
the given range, use the prandom_u32_max() function, which only takes
the minimum required bytes from the RNG and avoids divisions. This was
done mechanically with this coccinelle script:

@basic@
expression E;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
typedef u64;
@@
(
- ((T)get_random_u32() % (E))
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ((E) - 1))
+ prandom_u32_max(E * XXX_MAKE_SURE_E_IS_POW2)
|
- ((u64)(E) * get_random_u32() >> 32)
+ prandom_u32_max(E)
|
- ((T)get_random_u32() & ~PAGE_MASK)
+ prandom_u32_max(PAGE_SIZE)
)

@multi_line@
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
identifier RAND;
expression E;
@@

-       RAND = get_random_u32();
        ... when != RAND
-       RAND %= (E);
+       RAND = prandom_u32_max(E);

// Find a potential literal
@literal_mask@
expression LITERAL;
type T;
identifier get_random_u32 =~ "get_random_int|prandom_u32|get_random_u32";
position p;
@@

        ((T)get_random_u32()@p & (LITERAL))

// Add one to the literal.
@script:python add_one@
literal << literal_mask.LITERAL;
RESULT;
@@

value = None
if literal.startswith('0x'):
        value = int(literal, 16)
elif literal[0] in '123456789':
        value = int(literal, 10)
if value is None:
        print("I don't know how to handle %s" % (literal))
        cocci.include_match(False)
elif value == 2**32 - 1 or value == 2**31 - 1 or value == 2**24 - 1 or value == 2**16 - 1 or value == 2**8 - 1:
        print("Skipping 0x%x for cleanup elsewhere" % (value))
        cocci.include_match(False)
elif value & (value + 1) != 0:
        print("Skipping 0x%x because it's not a power of two minus one" % (value))
        cocci.include_match(False)
elif literal.startswith('0x'):
        coccinelle.RESULT = cocci.make_expr("0x%x" % (value + 1))
else:
        coccinelle.RESULT = cocci.make_expr("%d" % (value + 1))

// Replace the literal mask with the calculated result.
@plus_one@
expression literal_mask.LITERAL;
position literal_mask.p;
expression add_one.RESULT;
identifier FUNC;
@@

-       (FUNC()@p & (LITERAL))
+       prandom_u32_max(RESULT)

@collapse_ret@
type T;
identifier VAR;
expression E;
@@

 {
-       T VAR;
-       VAR = (E);
-       return VAR;
+       return E;
 }

@drop_var@
type T;
identifier VAR;
@@

 {
-       T VAR;
        ... when != VAR
 }

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: KP Singh <kpsingh@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> # for drbd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-10-11 17:42:55 -06:00
Linus Torvalds
f721d24e5d tmpfile API change
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Merge tag 'pull-tmpfile' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs tmpfile updates from Al Viro:
 "Miklos' ->tmpfile() signature change; pass an unopened struct file to
  it, let it open the damn thing. Allows to add tmpfile support to FUSE"

* tag 'pull-tmpfile' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fuse: implement ->tmpfile()
  vfs: open inside ->tmpfile()
  vfs: move open right after ->tmpfile()
  vfs: make vfs_tmpfile() static
  ovl: use vfs_tmpfile_open() helper
  cachefiles: use vfs_tmpfile_open() helper
  cachefiles: only pass inode to *mark_inode_inuse() helpers
  cachefiles: tmpfile error handling cleanup
  hugetlbfs: cleanup mknod and tmpfile
  vfs: add vfs_tmpfile_open() helper
2022-10-10 19:45:17 -07:00
Linus Torvalds
27bc50fc90 - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
linux-next for a couple of months without, to my knowledge, any negative
   reports (or any positive ones, come to that).
 
 - Also the Maple Tree from Liam R.  Howlett.  An overlapping range-based
   tree for vmas.  It it apparently slight more efficient in its own right,
   but is mainly targeted at enabling work to reduce mmap_lock contention.
 
   Liam has identified a number of other tree users in the kernel which
   could be beneficially onverted to mapletrees.
 
   Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
   (https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com).
   This has yet to be addressed due to Liam's unfortunately timed
   vacation.  He is now back and we'll get this fixed up.
 
 - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer.  It uses
   clang-generated instrumentation to detect used-unintialized bugs down to
   the single bit level.
 
   KMSAN keeps finding bugs.  New ones, as well as the legacy ones.
 
 - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
   memory into THPs.
 
 - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to support
   file/shmem-backed pages.
 
 - userfaultfd updates from Axel Rasmussen
 
 - zsmalloc cleanups from Alexey Romanov
 
 - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and memory-failure
 
 - Huang Ying adds enhancements to NUMA balancing memory tiering mode's
   page promotion, with a new way of detecting hot pages.
 
 - memcg updates from Shakeel Butt: charging optimizations and reduced
   memory consumption.
 
 - memcg cleanups from Kairui Song.
 
 - memcg fixes and cleanups from Johannes Weiner.
 
 - Vishal Moola provides more folio conversions
 
 - Zhang Yi removed ll_rw_block() :(
 
 - migration enhancements from Peter Xu
 
 - migration error-path bugfixes from Huang Ying
 
 - Aneesh Kumar added ability for a device driver to alter the memory
   tiering promotion paths.  For optimizations by PMEM drivers, DRM
   drivers, etc.
 
 - vma merging improvements from Jakub Matěn.
 
 - NUMA hinting cleanups from David Hildenbrand.
 
 - xu xin added aditional userspace visibility into KSM merging activity.
 
 - THP & KSM code consolidation from Qi Zheng.
 
 - more folio work from Matthew Wilcox.
 
 - KASAN updates from Andrey Konovalov.
 
 - DAMON cleanups from Kaixu Xia.
 
 - DAMON work from SeongJae Park: fixes, cleanups.
 
 - hugetlb sysfs cleanups from Muchun Song.
 
 - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.
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Merge tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in
   linux-next for a couple of months without, to my knowledge, any
   negative reports (or any positive ones, come to that).

 - Also the Maple Tree from Liam Howlett. An overlapping range-based
   tree for vmas. It it apparently slightly more efficient in its own
   right, but is mainly targeted at enabling work to reduce mmap_lock
   contention.

   Liam has identified a number of other tree users in the kernel which
   could be beneficially onverted to mapletrees.

   Yu Zhao has identified a hard-to-hit but "easy to fix" lockdep splat
   at [1]. This has yet to be addressed due to Liam's unfortunately
   timed vacation. He is now back and we'll get this fixed up.

 - Dmitry Vyukov introduces KMSAN: the Kernel Memory Sanitizer. It uses
   clang-generated instrumentation to detect used-unintialized bugs down
   to the single bit level.

   KMSAN keeps finding bugs. New ones, as well as the legacy ones.

 - Yang Shi adds a userspace mechanism (madvise) to induce a collapse of
   memory into THPs.

 - Zach O'Keefe has expanded Yang Shi's madvise(MADV_COLLAPSE) to
   support file/shmem-backed pages.

 - userfaultfd updates from Axel Rasmussen

 - zsmalloc cleanups from Alexey Romanov

 - cleanups from Miaohe Lin: vmscan, hugetlb_cgroup, hugetlb and
   memory-failure

 - Huang Ying adds enhancements to NUMA balancing memory tiering mode's
   page promotion, with a new way of detecting hot pages.

 - memcg updates from Shakeel Butt: charging optimizations and reduced
   memory consumption.

 - memcg cleanups from Kairui Song.

 - memcg fixes and cleanups from Johannes Weiner.

 - Vishal Moola provides more folio conversions

 - Zhang Yi removed ll_rw_block() :(

 - migration enhancements from Peter Xu

 - migration error-path bugfixes from Huang Ying

 - Aneesh Kumar added ability for a device driver to alter the memory
   tiering promotion paths. For optimizations by PMEM drivers, DRM
   drivers, etc.

 - vma merging improvements from Jakub Matěn.

 - NUMA hinting cleanups from David Hildenbrand.

 - xu xin added aditional userspace visibility into KSM merging
   activity.

 - THP & KSM code consolidation from Qi Zheng.

 - more folio work from Matthew Wilcox.

 - KASAN updates from Andrey Konovalov.

 - DAMON cleanups from Kaixu Xia.

 - DAMON work from SeongJae Park: fixes, cleanups.

 - hugetlb sysfs cleanups from Muchun Song.

 - Mike Kravetz fixes locking issues in hugetlbfs and in hugetlb core.

Link: https://lkml.kernel.org/r/CAOUHufZabH85CeUN-MEMgL8gJGzJEWUrkiM58JkTbBhh-jew0Q@mail.gmail.com [1]

* tag 'mm-stable-2022-10-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (555 commits)
  hugetlb: allocate vma lock for all sharable vmas
  hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
  hugetlb: fix vma lock handling during split vma and range unmapping
  mglru: mm/vmscan.c: fix imprecise comments
  mm/mglru: don't sync disk for each aging cycle
  mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol
  mm: memcontrol: use do_memsw_account() in a few more places
  mm: memcontrol: deprecate swapaccounting=0 mode
  mm: memcontrol: don't allocate cgroup swap arrays when memcg is disabled
  mm/secretmem: remove reduntant return value
  mm/hugetlb: add available_huge_pages() func
  mm: remove unused inline functions from include/linux/mm_inline.h
  selftests/vm: add selftest for MADV_COLLAPSE of uffd-minor memory
  selftests/vm: add file/shmem MADV_COLLAPSE selftest for cleared pmd
  selftests/vm: add thp collapse shmem testing
  selftests/vm: add thp collapse file and tmpfs testing
  selftests/vm: modularize thp collapse memory operations
  selftests/vm: dedup THP helpers
  mm/khugepaged: add tracepoint to hpage_collapse_scan_file()
  mm/madvise: add file and shmem support to MADV_COLLAPSE
  ...
2022-10-10 17:53:04 -07:00
Linus Torvalds
adf4bfc4a9 cgroup changes for v6.1-rc1.
* cpuset now support isolated cpus.partition type, which will enable dynamic
   CPU isolation.
 * pids.peak added to remember the max number of pids used.
 * Holes in cgroup namespace plugged.
 * Internal cleanups.
 
 Note that for-6.1-fixes was pulled into for-6.1 twice. Both were for
 follow-up cleanups and each merge commit has details.
 
 Also, 8a693f7766 ("cgroup: Remove CFTYPE_PRESSURE") removes the flag used
 by PSI changes in the tip tree and the merged result won't compile due to
 the missing flag. Simply removing the struct init lines specifying the flag
 is the correct resolution. linux-next already contains the correct fix:
 
  https://lkml.kernel.org/r/20220912161812.072aaa3b@canb.auug.org.au
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Merge tag 'cgroup-for-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup updates from Tejun Heo:

 - cpuset now support isolated cpus.partition type, which will enable
   dynamic CPU isolation

 - pids.peak added to remember the max number of pids used

 - holes in cgroup namespace plugged

 - internal cleanups

* tag 'cgroup-for-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (25 commits)
  cgroup: use strscpy() is more robust and safer
  iocost_monitor: reorder BlkgIterator
  cgroup: simplify code in cgroup_apply_control
  cgroup: Make cgroup_get_from_id() prettier
  cgroup/cpuset: remove unreachable code
  cgroup: Remove CFTYPE_PRESSURE
  cgroup: Improve cftype add/rm error handling
  kselftest/cgroup: Add cpuset v2 partition root state test
  cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst
  cgroup/cpuset: Make partition invalid if cpumask change violates exclusivity rule
  cgroup/cpuset: Relocate a code block in validate_change()
  cgroup/cpuset: Show invalid partition reason string
  cgroup/cpuset: Add a new isolated cpus.partition type
  cgroup/cpuset: Relax constraints to partition & cpus changes
  cgroup/cpuset: Allow no-task partition to have empty cpuset.cpus.effective
  cgroup/cpuset: Miscellaneous cleanups & add helper functions
  cgroup/cpuset: Enable update_tasks_cpumask() on top_cpuset
  cgroup: add pids.peak interface for pids controller
  cgroup: Remove data-race around cgrp_dfl_visible
  cgroup: Fix build failure when CONFIG_SHRINKER_DEBUG
  ...
2022-10-10 11:12:25 -07:00
Linus Torvalds
8adc0486f3 Random number generator updates for Linux 6.1-rc1.
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Merge tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random

Pull random number generator updates from Jason Donenfeld:

 - Huawei reported that when they updated their kernel from 4.4 to
   something much newer, some userspace code they had broke, the culprit
   being the accidental removal of O_NONBLOCK from /dev/random way back
   in 5.6. It's been gone for over 2 years now and this is the first
   we've heard of it, but userspace breakage is userspace breakage, so
   O_NONBLOCK is now back.

 - Use randomness from hardware RNGs much more often during early boot,
   at the same interval that crng reseeds are done, from Dominik.

 - A semantic change in hardware RNG throttling, so that the hwrng
   framework can properly feed random.c with randomness from hardware
   RNGs that aren't specifically marked as creditable.

   A related patch coming to you via Herbert's hwrng tree depends on
   this one, not to compile, but just to function properly, so you may
   want to merge this PULL before that one.

 - A fix to clamp credited bits from the interrupts pool to the size of
   the pool sample. This is mainly just a theoretical fix, as it'd be
   pretty hard to exceed it in practice.

 - Oracle reported that InfiniBand TCP latency regressed by around
   10-15% after a change a few cycles ago made at the request of the RT
   folks, in which we hoisted a somewhat rare operation (1 in 1024
   times) out of the hard IRQ handler and into a workqueue, a pretty
   common and boring pattern.

   It turns out, though, that scheduling a worker from there has
   overhead of its own, whereas scheduling a timer on that same CPU for
   the next jiffy amortizes better and doesn't incur the same overhead.

   I also eliminated a cache miss by moving the work_struct (and
   subsequently, the timer_list) to below a critical cache line, so that
   the more critical members that are accessed on every hard IRQ aren't
   split between two cache lines.

 - The boot-time initialization of the RNG has been split into two
   approximate phases: what we can accomplish before timekeeping is
   possible and what we can accomplish after.

   This winds up being useful so that we can use RDRAND to seed the RNG
   before CONFIG_SLAB_FREELIST_RANDOM=y systems initialize slabs, in
   addition to other early uses of randomness. The effect is that
   systems with RDRAND (or a bootloader seed) will never see any
   warnings at all when setting CONFIG_WARN_ALL_UNSEEDED_RANDOM=y. And
   kfence benefits from getting a better seed of its own.

 - Small systems without much entropy sometimes wind up putting some
   truncated serial number read from flash into hostname, so contribute
   utsname changes to the RNG, without crediting.

 - Add smaller batches to serve requests for smaller integers, and make
   use of them when people ask for random numbers bounded by a given
   compile-time constant. This has positive effects all over the tree,
   most notably in networking and kfence.

 - The original jitter algorithm intended (I believe) to schedule the
   timer for the next jiffy, not the next-next jiffy, yet it used
   mod_timer(jiffies + 1), which will fire on the next-next jiffy,
   instead of what I believe was intended, mod_timer(jiffies), which
   will fire on the next jiffy. So fix that.

 - Fix a comment typo, from William.

* tag 'random-6.1-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  random: clear new batches when bringing new CPUs online
  random: fix typos in get_random_bytes() comment
  random: schedule jitter credit for next jiffy, not in two jiffies
  prandom: make use of smaller types in prandom_u32_max
  random: add 8-bit and 16-bit batches
  utsname: contribute changes to RNG
  random: use init_utsname() instead of utsname()
  kfence: use better stack hash seed
  random: split initialization into early step and later step
  random: use expired timer rather than wq for mixing fast pool
  random: avoid reading two cache lines on irq randomness
  random: clamp credited irq bits to maximum mixed
  random: throttle hwrng writes if no entropy is credited
  random: use hwgenerator randomness more frequently at early boot
  random: restore O_NONBLOCK support
2022-10-10 10:41:21 -07:00
Linus Torvalds
52abb27abf slab fixes for 6.1-rc1
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Merge tag 'slab-for-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab fixes from Vlastimil Babka:

 - The "common kmalloc v4" series [1] by Hyeonggon Yoo.

   While the plan after LPC is to try again if it's possible to get rid
   of SLOB and SLAB (and if any critical aspect of those is not possible
   to achieve with SLUB today, modify it accordingly), it will take a
   while even in case there are no objections.

   Meanwhile this is a nice cleanup and some parts (e.g. to the
   tracepoints) will be useful even if we end up with a single slab
   implementation in the future:

      - Improves the mm/slab_common.c wrappers to allow deleting
        duplicated code between SLAB and SLUB.

      - Large kmalloc() allocations in SLAB are passed to page allocator
        like in SLUB, reducing number of kmalloc caches.

      - Removes the {kmem_cache_alloc,kmalloc}_node variants of
        tracepoints, node id parameter added to non-_node variants.

 - Addition of kmalloc_size_roundup()

   The first two patches from a series by Kees Cook [2] that introduce
   kmalloc_size_roundup(). This will allow merging of per-subsystem
   patches using the new function and ultimately stop (ab)using ksize()
   in a way that causes ongoing trouble for debugging functionality and
   static checkers.

 - Wasted kmalloc() memory tracking in debugfs alloc_traces

   A patch from Feng Tang that enhances the existing debugfs
   alloc_traces file for kmalloc caches with information about how much
   space is wasted by allocations that needs less space than the
   particular kmalloc cache provides.

 - My series [3] to fix validation races for caches with enabled
   debugging:

      - By decoupling the debug cache operation more from non-debug
        fastpaths, extra locking simplifications were possible and thus
        done afterwards.

      - Additional cleanup of PREEMPT_RT specific code on top, by Thomas
        Gleixner.

      - A late fix for slab page leaks caused by the series, by Feng
        Tang.

 - Smaller fixes and cleanups:

      - Unneeded variable removals, by ye xingchen

      - A cleanup removing a BUG_ON() in create_unique_id(), by Chao Yu

Link: https://lore.kernel.org/all/20220817101826.236819-1-42.hyeyoo@gmail.com/ [1]
Link: https://lore.kernel.org/all/20220923202822.2667581-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/all/20220823170400.26546-1-vbabka@suse.cz/ [3]

* tag 'slab-for-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (30 commits)
  mm/slub: fix a slab missed to be freed problem
  slab: Introduce kmalloc_size_roundup()
  slab: Remove __malloc attribute from realloc functions
  mm/slub: clean up create_unique_id()
  mm/slub: enable debugging memory wasting of kmalloc
  slub: Make PREEMPT_RT support less convoluted
  mm/slub: simplify __cmpxchg_double_slab() and slab_[un]lock()
  mm/slub: convert object_map_lock to non-raw spinlock
  mm/slub: remove slab_lock() usage for debug operations
  mm/slub: restrict sysfs validation to debug caches and make it safe
  mm/sl[au]b: check if large object is valid in __ksize()
  mm/slab_common: move declaration of __ksize() to mm/slab.h
  mm/slab_common: drop kmem_alloc & avoid dereferencing fields when not using
  mm/slab_common: unify NUMA and UMA version of tracepoints
  mm/sl[au]b: cleanup kmem_cache_alloc[_node]_trace()
  mm/sl[au]b: generalize kmalloc subsystem
  mm/slub: move free_debug_processing() further
  mm/sl[au]b: introduce common alloc/free functions without tracepoint
  mm/slab: kmalloc: pass requests larger than order-1 page to page allocator
  mm/slab_common: cleanup kmalloc_large()
  ...
2022-10-10 10:21:22 -07:00
Linus Torvalds
7f6dcffb44 Preempt RT cleanups:
Introduce preempt_[dis|enable_nested() and use it to clean up
  various places which have open coded PREEMPT_RT conditionals.
 
  On PREEMPT_RT enabled kernels, spinlocks and rwlocks are neither disabling
  preemption nor interrupts. Though there are a few places which depend on
  the implicit preemption/interrupt disable of those locks, e.g. seqcount
  write sections, per CPU statistics updates etc.
 
  PREEMPT_RT added open coded CONFIG_PREEMPT_RT conditionals to
  disable/enable preemption in the related code parts all over the
  place. That's hard to read and does not really explain why this is
  necessary.
 
  Linus suggested to use helper functions (preempt_disable_nested() and
  preempt_enable_nested()) and use those in the affected places. On !RT
  enabled kernels these functions are NOPs, but contain a lockdep assert to
  validate that preemption is actually disabled to catch call sites which
  do not have preemption disabled.
 
  Clean up the affected code paths in mm, dentry and lib.
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Merge tag 'sched-rt-2022-10-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull preempt RT updates from Thomas Gleixner:
 "Introduce preempt_[dis|enable_nested() and use it to clean up various
  places which have open coded PREEMPT_RT conditionals.

  On PREEMPT_RT enabled kernels, spinlocks and rwlocks are neither
  disabling preemption nor interrupts. Though there are a few places
  which depend on the implicit preemption/interrupt disable of those
  locks, e.g. seqcount write sections, per CPU statistics updates etc.

  PREEMPT_RT added open coded CONFIG_PREEMPT_RT conditionals to
  disable/enable preemption in the related code parts all over the
  place. That's hard to read and does not really explain why this is
  necessary.

  Linus suggested to use helper functions (preempt_disable_nested() and
  preempt_enable_nested()) and use those in the affected places. On !RT
  enabled kernels these functions are NOPs, but contain a lockdep assert
  to validate that preemption is actually disabled to catch call sites
  which do not have preemption disabled.

  Clean up the affected code paths in mm, dentry and lib"

* tag 'sched-rt-2022-10-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  u64_stats: Streamline the implementation
  flex_proportions: Disable preemption entering the write section.
  mm/compaction: Get rid of RT ifdeffery
  mm/memcontrol: Replace the PREEMPT_RT conditionals
  mm/debug: Provide VM_WARN_ON_IRQS_ENABLED()
  mm/vmstat: Use preempt_[dis|en]able_nested()
  dentry: Use preempt_[dis|en]able_nested()
  preempt: Provide preempt_[dis|en]able_nested()
2022-10-10 10:03:24 -07:00
Linus Torvalds
30c999937f Scheduler changes for v6.1:
- Debuggability:
 
      - Change most occurances of BUG_ON() to WARN_ON_ONCE()
 
      - Reorganize & fix TASK_ state comparisons, turn it into a bitmap
 
      - Update/fix misc scheduler debugging facilities
 
  - Load-balancing & regular scheduling:
 
      - Improve the behavior of the scheduler in presence of lot of
        SCHED_IDLE tasks - in particular they should not impact other
        scheduling classes.
 
      - Optimize task load tracking, cleanups & fixes
 
      - Clean up & simplify misc load-balancing code
 
  - Freezer:
 
      - Rewrite the core freezer to behave better wrt thawing and be simpler
        in general, by replacing PF_FROZEN with TASK_FROZEN & fixing/adjusting
        all the fallout.
 
  - Deadline scheduler:
 
      - Fix the DL capacity-aware code
 
      - Factor out dl_task_is_earliest_deadline() & replenish_dl_new_period()
 
      - Relax/optimize locking in task_non_contending()
 
  - Cleanups:
 
      - Factor out the update_current_exec_runtime() helper
 
      - Various cleanups, simplifications
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:
 "Debuggability:

   - Change most occurances of BUG_ON() to WARN_ON_ONCE()

   - Reorganize & fix TASK_ state comparisons, turn it into a bitmap

   - Update/fix misc scheduler debugging facilities

  Load-balancing & regular scheduling:

   - Improve the behavior of the scheduler in presence of lot of
     SCHED_IDLE tasks - in particular they should not impact other
     scheduling classes.

   - Optimize task load tracking, cleanups & fixes

   - Clean up & simplify misc load-balancing code

  Freezer:

   - Rewrite the core freezer to behave better wrt thawing and be
     simpler in general, by replacing PF_FROZEN with TASK_FROZEN &
     fixing/adjusting all the fallout.

  Deadline scheduler:

   - Fix the DL capacity-aware code

   - Factor out dl_task_is_earliest_deadline() &
     replenish_dl_new_period()

   - Relax/optimize locking in task_non_contending()

  Cleanups:

   - Factor out the update_current_exec_runtime() helper

   - Various cleanups, simplifications"

* tag 'sched-core-2022-10-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits)
  sched: Fix more TASK_state comparisons
  sched: Fix TASK_state comparisons
  sched/fair: Move call to list_last_entry() in detach_tasks
  sched/fair: Cleanup loop_max and loop_break
  sched/fair: Make sure to try to detach at least one movable task
  sched: Show PF_flag holes
  freezer,sched: Rewrite core freezer logic
  sched: Widen TAKS_state literals
  sched/wait: Add wait_event_state()
  sched/completion: Add wait_for_completion_state()
  sched: Add TASK_ANY for wait_task_inactive()
  sched: Change wait_task_inactive()s match_state
  freezer,umh: Clean up freezer/initrd interaction
  freezer: Have {,un}lock_system_sleep() save/restore flags
  sched: Rename task_running() to task_on_cpu()
  sched/fair: Cleanup for SIS_PROP
  sched/fair: Default to false in test_idle_cores()
  sched/fair: Remove useless check in select_idle_core()
  sched/fair: Avoid double search on same cpu
  sched/fair: Remove redundant check in select_idle_smt()
  ...
2022-10-10 09:10:28 -07:00
Linus Torvalds
ef688f8b8c The first batch of KVM patches, mostly covering x86, which I
am sending out early due to me travelling next week.  There is a
 lone mm patch for which Andrew gave an informal ack at
 https://lore.kernel.org/linux-mm/20220817102500.440c6d0a3fce296fdf91bea6@linux-foundation.org.
 
 I will send the bulk of ARM work, as well as other
 architectures, at the end of next week.
 
 ARM:
 
 * Account stage2 page table allocations in memory stats.
 
 x86:
 
 * Account EPT/NPT arm64 page table allocations in memory stats.
 
 * Tracepoint cleanups/fixes for nested VM-Enter and emulated MSR accesses.
 
 * Drop eVMCS controls filtering for KVM on Hyper-V, all known versions of
   Hyper-V now support eVMCS fields associated with features that are
   enumerated to the guest.
 
 * Use KVM's sanitized VMCS config as the basis for the values of nested VMX
   capabilities MSRs.
 
 * A myriad event/exception fixes and cleanups.  Most notably, pending
   exceptions morph into VM-Exits earlier, as soon as the exception is
   queued, instead of waiting until the next vmentry.  This fixed
   a longstanding issue where the exceptions would incorrecly become
   double-faults instead of triggering a vmexit; the common case of
   page-fault vmexits had a special workaround, but now it's fixed
   for good.
 
 * A handful of fixes for memory leaks in error paths.
 
 * Cleanups for VMREAD trampoline and VMX's VM-Exit assembly flow.
 
 * Never write to memory from non-sleepable kvm_vcpu_check_block()
 
 * Selftests refinements and cleanups.
 
 * Misc typo cleanups.
 
 Generic:
 
 * remove KVM_REQ_UNHALT
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "The first batch of KVM patches, mostly covering x86.

  ARM:

   - Account stage2 page table allocations in memory stats

  x86:

   - Account EPT/NPT arm64 page table allocations in memory stats

   - Tracepoint cleanups/fixes for nested VM-Enter and emulated MSR
     accesses

   - Drop eVMCS controls filtering for KVM on Hyper-V, all known
     versions of Hyper-V now support eVMCS fields associated with
     features that are enumerated to the guest

   - Use KVM's sanitized VMCS config as the basis for the values of
     nested VMX capabilities MSRs

   - A myriad event/exception fixes and cleanups. Most notably, pending
     exceptions morph into VM-Exits earlier, as soon as the exception is
     queued, instead of waiting until the next vmentry. This fixed a
     longstanding issue where the exceptions would incorrecly become
     double-faults instead of triggering a vmexit; the common case of
     page-fault vmexits had a special workaround, but now it's fixed for
     good

   - A handful of fixes for memory leaks in error paths

   - Cleanups for VMREAD trampoline and VMX's VM-Exit assembly flow

   - Never write to memory from non-sleepable kvm_vcpu_check_block()

   - Selftests refinements and cleanups

   - Misc typo cleanups

  Generic:

   - remove KVM_REQ_UNHALT"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (94 commits)
  KVM: remove KVM_REQ_UNHALT
  KVM: mips, x86: do not rely on KVM_REQ_UNHALT
  KVM: x86: never write to memory from kvm_vcpu_check_block()
  KVM: x86: Don't snapshot pending INIT/SIPI prior to checking nested events
  KVM: nVMX: Make event request on VMXOFF iff INIT/SIPI is pending
  KVM: nVMX: Make an event request if INIT or SIPI is pending on VM-Enter
  KVM: SVM: Make an event request if INIT or SIPI is pending when GIF is set
  KVM: x86: lapic does not have to process INIT if it is blocked
  KVM: x86: Rename kvm_apic_has_events() to make it INIT/SIPI specific
  KVM: x86: Rename and expose helper to detect if INIT/SIPI are allowed
  KVM: nVMX: Make an event request when pending an MTF nested VM-Exit
  KVM: x86: make vendor code check for all nested events
  mailmap: Update Oliver's email address
  KVM: x86: Allow force_emulation_prefix to be written without a reload
  KVM: selftests: Add an x86-only test to verify nested exception queueing
  KVM: selftests: Use uapi header to get VMX and SVM exit reasons/codes
  KVM: x86: Rename inject_pending_events() to kvm_check_and_inject_events()
  KVM: VMX: Update MTF and ICEBP comments to document KVM's subtle behavior
  KVM: x86: Treat pending TRIPLE_FAULT requests as pending exceptions
  KVM: x86: Morph pending exceptions to pending VM-Exits at queue time
  ...
2022-10-09 09:39:55 -07:00
Mike Kravetz
bbff39cc6c hugetlb: allocate vma lock for all sharable vmas
The hugetlb vma lock was originally designed to synchronize pmd sharing. 
As such, it was only necessary to allocate the lock for vmas that were
capable of pmd sharing.  Later in the development cycle, it was discovered
that it could also be used to simplify fault/truncation races as described
in [1].  However, a subsequent change to allocate the lock for all vmas
that use the page cache was never made.  A fault/truncation race could
leave pages in a file past i_size until the file is removed.

Remove the previous restriction and allocate lock for all VM_MAYSHARE
vmas.  Warn in the unlikely event of allocation failure.

[1] https://lore.kernel.org/lkml/Yxiv0SkMkZ0JWGGp@monkey/#t

Link: https://lkml.kernel.org/r/20221005011707.514612-4-mike.kravetz@oracle.com
Fixes: "hugetlb: clean up code checking for fault/truncation races"
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-07 14:28:40 -07:00
Mike Kravetz
ecfbd73387 hugetlb: take hugetlb vma_lock when clearing vma_lock->vma pointer
hugetlb file truncation/hole punch code may need to back out and take
locks in order in the routine hugetlb_unmap_file_folio().  This code could
race with vma freeing as pointed out in [1] and result in accessing a
stale vma pointer.  To address this, take the vma_lock when clearing the
vma_lock->vma pointer.

[1] https://lore.kernel.org/linux-mm/01f10195-7088-4462-6def-909549c75ef4@huawei.com/

[mike.kravetz@oracle.com: address build issues]
  Link: https://lkml.kernel.org/r/Yz5L1uxQYR1VqFtJ@monkey
Link: https://lkml.kernel.org/r/20221005011707.514612-3-mike.kravetz@oracle.com
Fixes: "hugetlb: use new vma_lock for pmd sharing synchronization"
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-07 14:28:40 -07:00
Mike Kravetz
131a79b474 hugetlb: fix vma lock handling during split vma and range unmapping
Patch series "hugetlb: fixes for new vma lock series".

In review of the series "hugetlb: Use new vma lock for huge pmd sharing
synchronization", Miaohe Lin pointed out two key issues:

1) There is a race in the routine hugetlb_unmap_file_folio when locks
   are dropped and reacquired in the correct order [1].

2) With the switch to using vma lock for fault/truncate synchronization,
   we need to make sure lock exists for all VM_MAYSHARE vmas, not just
   vmas capable of pmd sharing.

These two issues are addressed here.  In addition, having a vma lock
present in all VM_MAYSHARE vmas, uncovered some issues around vma
splitting.  Those are also addressed.

[1] https://lore.kernel.org/linux-mm/01f10195-7088-4462-6def-909549c75ef4@huawei.com/


This patch (of 3):

The hugetlb vma lock hangs off the vm_private_data field and is specific
to the vma.  When vm_area_dup() is called as part of vma splitting, the
vma lock pointer is copied to the new vma.  This will result in issues
such as double freeing of the structure.  Update the hugetlb open vm_ops
to allocate a new vma lock for the new vma.

The routine __unmap_hugepage_range_final unconditionally unset VM_MAYSHARE
to prevent subsequent pmd sharing.  hugetlb_vma_lock_free attempted to
anticipate this by checking both VM_MAYSHARE and VM_SHARED.  However, if
only VM_MAYSHARE was set we would miss the free.  With the introduction of
the vma lock, a vma can not participate in pmd sharing if vm_private_data
is NULL.  Instead of clearing VM_MAYSHARE in __unmap_hugepage_range_final,
free the vma lock to prevent sharing.  Also, update the sharing code to
make sure vma lock is indeed a condition for pmd sharing. 
hugetlb_vma_lock_free can then key off VM_MAYSHARE and not miss any vmas.

Link: https://lkml.kernel.org/r/20221005011707.514612-1-mike.kravetz@oracle.com
Link: https://lkml.kernel.org/r/20221005011707.514612-2-mike.kravetz@oracle.com
Fixes: "hugetlb: add vma based lock for pmd sharing"
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-07 14:28:40 -07:00
Yu Zhao
e4fea72b14 mglru: mm/vmscan.c: fix imprecise comments
Link: https://lkml.kernel.org/r/YzSWfFI+MOeb1ils@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-07 14:28:40 -07:00