linux/mm
Will Deacon f4e177d126 mm/migrate.c: stabilise page count when migrating transparent hugepages
When migrating a transparent hugepage, migrate_misplaced_transhuge_page
guards itself against a concurrent fastgup of the page by checking that
the page count is equal to 2 before and after installing the new pmd.

If the page count changes, then the pmd is reverted back to the original
entry, however there is a small window where the new (possibly writable)
pmd is installed and the underlying page could be written by userspace.
Restoring the old pmd could therefore result in loss of data.

This patch fixes the problem by freezing the page count whilst updating
the page tables, which protects against a concurrent fastgup without the
need to restore the old pmd in the failure case (since the page count
can no longer change under our feet).

Link: http://lkml.kernel.org/r/1497349722-6731-4-git-send-email-will.deacon@arm.com
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Steve Capper <steve.capper@arm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:31 -07:00
..
kasan Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-10 10:30:46 -07:00
backing-dev.c bdi: Drop 'parent' argument from bdi_register[_va]() 2017-04-20 12:09:55 -06:00
balloon_compaction.c mm: balloon: use general non-lru movable page feature 2016-07-26 16:19:19 -07:00
bootmem.c mm/bootmem.c: cosmetic improvement of code readability 2017-02-22 16:41:29 -08:00
cleancache.c fs: switch ->s_uuid to uuid_t 2017-06-05 16:59:12 +02:00
cma_debug.c cma: Store a name in the cma structure 2017-04-18 20:41:12 +02:00
cma.c mm/cma.c: warn if the CMA area could not be activated 2017-07-10 16:32:31 -07:00
cma.h cma: Store a name in the cma structure 2017-04-18 20:41:12 +02:00
compaction.c mm, compaction: skip over holes in __reset_isolation_suitable 2017-07-06 16:24:32 -07:00
debug_page_ref.c mm/page_ref: add tracepoint to track down page reference manipulation 2016-03-17 15:09:34 -07:00
debug.c mm, debug: print raw struct page data in __dump_page() 2016-12-12 18:55:08 -08:00
dmapool.c lib/vsprintf.c: remove %Z support 2017-02-27 18:43:47 -08:00
early_ioremap.c
fadvise.c mm: fadvise: avoid expensive remote LRU cache draining after FADV_DONTNEED 2016-12-20 09:48:46 -08:00
failslab.c mm: fault-inject take over bootstrap kmem_cache check 2016-03-15 16:55:16 -07:00
filemap.c mm: hugetlb: return immediately for hugetlb page in __delete_from_page_cache() 2017-07-10 16:32:30 -07:00
frame_vector.c treewide: use kv[mz]alloc* rather than opencoded variants 2017-05-08 17:15:13 -07:00
frontswap.c mm, frontswap: convert frontswap_enabled to static key 2016-07-26 16:19:19 -07:00
gup.c mm, gup: ensure real head page is ref-counted when using hugepages 2017-07-06 16:24:34 -07:00
highmem.c mm/highmem: make nr_free_highpages() handles all highmem zones by itself 2016-05-19 19:12:14 -07:00
huge_memory.c mm, THP, swap: check whether THP can be split firstly 2017-07-06 16:24:31 -07:00
hugetlb_cgroup.c mm, hugetlb_cgroup: round limit_in_bytes down to hugepage size 2016-05-20 17:58:30 -07:00
hugetlb.c mm/hugetlb.c: warn the user when issues arise on boot due to hugepages 2017-07-10 16:32:31 -07:00
hwpoison-inject.c mm: hwpoison: call shake_page() unconditionally 2017-05-03 15:52:12 -07:00
init-mm.c mm: Add a user_ns owner to mm_struct and fix ptrace permission checks 2016-11-22 11:49:48 -06:00
internal.h mm, compaction: finish whole pageblock to reduce fragmentation 2017-05-08 17:15:10 -07:00
interval_tree.c
Kconfig powerpc updates for 4.13 2017-07-07 13:55:45 -07:00
Kconfig.debug mm: enable page poisoning early at boot 2017-05-03 15:52:10 -07:00
khugepaged.c mm: make PR_SET_THP_DISABLE immediately active 2017-07-10 16:32:31 -07:00
kmemcheck.c mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU 2017-04-18 11:42:36 -07:00
kmemleak-test.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
kmemleak.c mm: kmemleak: treat vm_struct as alternative reference to vmalloc'ed objects 2017-07-06 16:24:34 -07:00
ksm.c ksm: optimize refile of stable_node_dup at the head of the chain 2017-07-06 16:24:31 -07:00
list_lru.c mm/list_lru.c: avoid error-path NULL pointer deref 2016-10-27 18:43:42 -07:00
maccess.c x86: remove more uaccess_32.h complexity 2016-05-22 17:21:27 -07:00
madvise.c swap: add block io poll in swapin path 2017-07-10 16:32:30 -07:00
Makefile percpu: expose statistics about percpu memory via debugfs 2017-06-20 15:31:38 -04:00
memblock.c mm, memory_hotplug: move movable_node to the hotplug proper 2017-07-06 16:24:35 -07:00
memcontrol.c mm/memcontrol: exclude @root from checks in mem_cgroup_low 2017-07-10 16:32:31 -07:00
memory_hotplug.c mm/memory_hotplug.c: add NULL check to avoid potential NULL pointer dereference 2017-07-10 16:32:30 -07:00
memory-failure.c mm: hwpoison: introduce idenfity_page_state 2017-07-10 16:32:30 -07:00
memory.c mm/memory.c: convert to DEFINE_DEBUGFS_ATTRIBUTE 2017-07-10 16:32:30 -07:00
mempolicy.c mm, mempolicy: don't check cpuset seqlock where it doesn't matter 2017-07-06 16:24:34 -07:00
mempool.c sched/wait: Rename wait_queue_t => wait_queue_entry_t 2017-06-20 12:18:27 +02:00
memtest.c
migrate.c mm/migrate.c: stabilise page count when migrating transparent hugepages 2017-07-10 16:32:31 -07:00
mincore.c mm: remove shmem_mapping() shmem_zero_setup() duplicates 2017-02-24 17:46:56 -08:00
mlock.c mlock: fix mlock count can not decrease in race condition 2017-06-02 15:07:38 -07:00
mm_init.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
mmap.c Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2017-07-08 12:17:25 -07:00
mmu_context.c sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
mmu_notifier.c mm: Use static initialization for "srcu" 2017-04-18 11:38:22 -07:00
mmzone.c mm/mmzone.c: swap likely to unlikely as code logic is different for next_zones_zonelist() 2017-02-22 16:41:29 -08:00
mprotect.c mm: drop NULL return check of pte_offset_map_lock() 2017-07-06 16:24:33 -07:00
mremap.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
msync.c
nobootmem.c mm/nobootmem.c: return 0 when start_pfn equals end_pfn 2017-07-06 16:24:31 -07:00
nommu.c mm, vmalloc: use __GFP_HIGHMEM implicitly 2017-05-08 17:15:13 -07:00
oom_kill.c mm/oom_kill: count global and memory cgroup oom kills 2017-07-06 16:24:35 -07:00
page_alloc.c mm, page_alloc: fallback to smallest page when not stealing whole pageblock 2017-07-10 16:32:30 -07:00
page_counter.c
page_ext.c mm: enable page poisoning early at boot 2017-05-03 15:52:10 -07:00
page_idle.c mm: make rmap_one boolean function 2017-05-03 15:52:10 -07:00
page_io.c swap: add block io poll in swapin path 2017-07-10 16:32:30 -07:00
page_isolation.c mm: __first_valid_page skip over offline pages 2017-07-06 16:24:32 -07:00
page_owner.c mm/page_owner: don't define fields on struct page_ext by hard-coding 2016-10-07 18:46:27 -07:00
page_poison.c mm: enable page poisoning early at boot 2017-05-03 15:52:10 -07:00
page_vma_mapped.c mm/hugetlb: add size parameter to huge_pte_offset() 2017-07-06 16:24:34 -07:00
page-writeback.c Writeback error handling fixes (pile #1) 2017-07-07 18:39:15 -07:00
pagewalk.c mm/hugetlb: add size parameter to huge_pte_offset() 2017-07-06 16:24:34 -07:00
percpu-internal.h percpu: fix early calls for spinlock in pcpu_stats 2017-06-21 13:53:52 -04:00
percpu-km.c percpu: fix static checker warnings in pcpu_destroy_chunk 2017-06-29 11:23:38 -04:00
percpu-stats.c percpu: expose statistics about percpu memory via debugfs 2017-06-20 15:31:38 -04:00
percpu-vm.c percpu: fix static checker warnings in pcpu_destroy_chunk 2017-06-29 11:23:38 -04:00
percpu.c percpu: resolve err may not be initialized in pcpu_alloc 2017-06-21 12:00:45 -04:00
pgtable-generic.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
process_vm_access.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/mm.h> 2017-03-02 08:42:28 +01:00
quicklist.c fix Christoph's email addresses 2016-03-17 15:09:34 -07:00
readahead.c mm: don't cap request size based on read-ahead setting 2016-12-12 18:55:08 -08:00
rmap.c mm: memcontrol: per-lruvec stats infrastructure 2017-07-06 16:24:35 -07:00
rodata_test.c mm: remove rodata_test_data export, add pr_fmt 2017-05-03 15:52:09 -07:00
shmem.c mm: make PR_SET_THP_DISABLE immediately active 2017-07-10 16:32:31 -07:00
slab_common.c mm: allow slab_nomerge to be set at build time 2017-07-06 16:24:31 -07:00
slab.c mm: memcontrol: account slab stats per lruvec 2017-07-06 16:24:35 -07:00
slab.h mm: memcontrol: account slab stats per lruvec 2017-07-06 16:24:35 -07:00
slob.c mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU 2017-04-18 11:42:36 -07:00
slub.c mm: memcontrol: account slab stats per lruvec 2017-07-06 16:24:35 -07:00
sparse-vmemmap.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
sparse.c mm, memory_hotplug: do not associate hotadded memory to zones until online 2017-07-06 16:24:32 -07:00
swap_cgroup.c mm, THP, swap: delay splitting THP during swap out 2017-07-06 16:24:31 -07:00
swap_slots.c mm, THP, swap: delay splitting THP during swap out 2017-07-06 16:24:31 -07:00
swap_state.c swap: add block io poll in swapin path 2017-07-10 16:32:30 -07:00
swap.c mm: per-cgroup memory reclaim stats 2017-07-06 16:24:35 -07:00
swapfile.c swap: add block io poll in swapin path 2017-07-10 16:32:30 -07:00
truncate.c mm: fix data corruption due to stale mmap reads 2017-05-12 15:57:15 -07:00
usercopy.c mm/usercopy: Drop extra is_vmalloc_or_module() check 2017-04-05 12:30:18 -07:00
userfaultfd.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
util.c mm: clarify why we want kmalloc before falling backto vmallock 2017-06-02 15:07:37 -07:00
vmacache.c sched/headers: Prepare to move 'init_task' and 'init_thread_union' from <linux/sched.h> to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
vmalloc.c vmalloc: show lazy-purged vma info in vmallocinfo 2017-07-10 16:32:31 -07:00
vmpressure.c mm, vmpressure: pass-through notification support 2017-07-10 16:32:31 -07:00
vmscan.c mm, vmscan: avoid thrashing anon lru when free + file is low 2017-07-10 16:32:30 -07:00
vmstat.c mm: vmstat: move slab statistics from zone to node counters 2017-07-06 16:24:35 -07:00
workingset.c mm: memcontrol: per-lruvec stats infrastructure 2017-07-06 16:24:35 -07:00
z3fold.c z3fold: fix page locking in z3fold_alloc() 2017-04-13 18:24:20 -07:00
zbud.c
zpool.c
zsmalloc.c mm/zsmalloc.c: fix -Wunneeded-internal-declaration warning 2017-07-10 16:32:30 -07:00
zswap.c mm/zswap.c: delete an error message for a failed memory allocation in zswap_dstmem_prepare() 2017-07-06 16:24:35 -07:00