https://github.com/torvalds/linux
Revision d75450ff40df0199bf13dfb19f435519ff947138 authored by Hugh Dickins on 07 April 2017, 23:04:39 UTC, committed by Linus Torvalds on 08 April 2017, 07:47:48 UTC
Doug Smythies reports oops with KSM in this backtrace, I've been seeing the same: page_vma_mapped_walk+0xe6/0x5b0 page_referenced_one+0x91/0x1a0 rmap_walk_ksm+0x100/0x190 rmap_walk+0x4f/0x60 page_referenced+0x149/0x170 shrink_active_list+0x1c2/0x430 shrink_node_memcg+0x67a/0x7a0 shrink_node+0xe1/0x320 kswapd+0x34b/0x720 Just as observed in commit 4b0ece6fa016 ("mm: migrate: fix remove_migration_pte() for ksm pages"), you cannot use page->index calculations on ksm pages. page_vma_mapped_walk() is relying on __vma_address(), where a ksm page can lead it off the end of the page table, and into whatever nonsense is in the next page, ending as an oops inside check_pte()'s pte_page(). KSM tells page_vma_mapped_walk() exactly where to look for the page, it does not need any page->index calculation: and that's so also for all the normal and file and anon pages - just not for THPs and their subpages. Get out early in most cases: instead of a PageKsm test, move down the earlier not-THP-page test, as suggested by Kirill. I'm also slightly worried that this loop can stray into other vmas, so added a vm_end test to prevent surprises; though I have not imagined anything worse than a very contrived case, in which a page mlocked in the next vma might be reclaimed because it is not mlocked in this vma. Fixes: ace71a19cec5 ("mm: introduce page_vma_mapped_walk()") Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1704031104400.1118@eggly.anvils Signed-off-by: Hugh Dickins <hughd@google.com> Reported-by: Doug Smythies <dsmythies@telus.net> Tested-by: Doug Smythies <dsmythies@telus.net> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tip revision: d75450ff40df0199bf13dfb19f435519ff947138 authored by Hugh Dickins on 07 April 2017, 23:04:39 UTC
mm: fix page_vma_mapped_walk() for ksm pages
mm: fix page_vma_mapped_walk() for ksm pages
Tip revision: d75450f
File | Mode | Size |
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Kconfig | -rw-r--r-- | 23.9 KB |
Kconfig.debug | -rw-r--r-- | 3.8 KB |
Makefile | -rw-r--r-- | 3.5 KB |
backing-dev.c | -rw-r--r-- | 27.3 KB |
balloon_compaction.c | -rw-r--r-- | 4.7 KB |
bootmem.c | -rw-r--r-- | 20.8 KB |
cleancache.c | -rw-r--r-- | 9.9 KB |
cma.c | -rw-r--r-- | 13.0 KB |
cma.h | -rw-r--r-- | 515 bytes |
cma_debug.c | -rw-r--r-- | 4.5 KB |
compaction.c | -rw-r--r-- | 57.2 KB |
debug.c | -rw-r--r-- | 4.3 KB |
debug_page_ref.c | -rw-r--r-- | 1.3 KB |
dmapool.c | -rw-r--r-- | 13.7 KB |
early_ioremap.c | -rw-r--r-- | 6.2 KB |
fadvise.c | -rw-r--r-- | 4.3 KB |
failslab.c | -rw-r--r-- | 1.4 KB |
filemap.c | -rw-r--r-- | 80.0 KB |
frame_vector.c | -rw-r--r-- | 6.1 KB |
frontswap.c | -rw-r--r-- | 14.3 KB |
gup.c | -rw-r--r-- | 43.6 KB |
highmem.c | -rw-r--r-- | 11.7 KB |
huge_memory.c | -rw-r--r-- | 73.0 KB |
hugetlb.c | -rw-r--r-- | 127.8 KB |
hugetlb_cgroup.c | -rw-r--r-- | 10.9 KB |
hwpoison-inject.c | -rw-r--r-- | 3.2 KB |
init-mm.c | -rw-r--r-- | 680 bytes |
internal.h | -rw-r--r-- | 15.6 KB |
interval_tree.c | -rw-r--r-- | 3.1 KB |
khugepaged.c | -rw-r--r-- | 48.5 KB |
kmemcheck.c | -rw-r--r-- | 2.9 KB |
kmemleak-test.c | -rw-r--r-- | 3.2 KB |
kmemleak.c | -rw-r--r-- | 56.2 KB |
ksm.c | -rw-r--r-- | 65.5 KB |
list_lru.c | -rw-r--r-- | 12.6 KB |
maccess.c | -rw-r--r-- | 3.0 KB |
madvise.c | -rw-r--r-- | 21.6 KB |
memblock.c | -rw-r--r-- | 49.5 KB |
memcontrol.c | -rw-r--r-- | 154.7 KB |
memory-failure.c | -rw-r--r-- | 49.2 KB |
memory.c | -rw-r--r-- | 117.9 KB |
memory_hotplug.c | -rw-r--r-- | 55.4 KB |
mempolicy.c | -rw-r--r-- | 71.3 KB |
mempool.c | -rw-r--r-- | 13.9 KB |
memtest.c | -rw-r--r-- | 2.7 KB |
migrate.c | -rw-r--r-- | 52.2 KB |
mincore.c | -rw-r--r-- | 6.7 KB |
mlock.c | -rw-r--r-- | 22.6 KB |
mm_init.c | -rw-r--r-- | 4.8 KB |
mmap.c | -rw-r--r-- | 95.3 KB |
mmu_context.c | -rw-r--r-- | 1.3 KB |
mmu_notifier.c | -rw-r--r-- | 11.7 KB |
mmzone.c | -rw-r--r-- | 2.4 KB |
mprotect.c | -rw-r--r-- | 13.5 KB |
mremap.c | -rw-r--r-- | 16.2 KB |
msync.c | -rw-r--r-- | 2.6 KB |
nobootmem.c | -rw-r--r-- | 11.1 KB |
nommu.c | -rw-r--r-- | 48.5 KB |
oom_kill.c | -rw-r--r-- | 28.4 KB |
page-writeback.c | -rw-r--r-- | 84.5 KB |
page_alloc.c | -rw-r--r-- | 207.7 KB |
page_counter.c | -rw-r--r-- | 4.8 KB |
page_ext.c | -rw-r--r-- | 11.4 KB |
page_idle.c | -rw-r--r-- | 5.4 KB |
page_io.c | -rw-r--r-- | 9.4 KB |
page_isolation.c | -rw-r--r-- | 8.3 KB |
page_owner.c | -rw-r--r-- | 14.7 KB |
page_poison.c | -rw-r--r-- | 3.5 KB |
page_vma_mapped.c | -rw-r--r-- | 5.8 KB |
pagewalk.c | -rw-r--r-- | 8.4 KB |
percpu-km.c | -rw-r--r-- | 2.8 KB |
percpu-vm.c | -rw-r--r-- | 10.0 KB |
percpu.c | -rw-r--r-- | 66.5 KB |
pgtable-generic.c | -rw-r--r-- | 5.2 KB |
process_vm_access.c | -rw-r--r-- | 10.1 KB |
quicklist.c | -rw-r--r-- | 2.4 KB |
readahead.c | -rw-r--r-- | 16.1 KB |
rmap.c | -rw-r--r-- | 48.6 KB |
rodata_test.c | -rw-r--r-- | 1.5 KB |
shmem.c | -rw-r--r-- | 110.3 KB |
slab.c | -rw-r--r-- | 110.3 KB |
slab.h | -rw-r--r-- | 14.7 KB |
slab_common.c | -rw-r--r-- | 34.4 KB |
slob.c | -rw-r--r-- | 16.0 KB |
slub.c | -rw-r--r-- | 140.2 KB |
sparse-vmemmap.c | -rw-r--r-- | 8.1 KB |
sparse.c | -rw-r--r-- | 20.8 KB |
swap.c | -rw-r--r-- | 26.9 KB |
swap_cgroup.c | -rw-r--r-- | 4.6 KB |
swap_slots.c | -rw-r--r-- | 8.8 KB |
swap_state.c | -rw-r--r-- | 14.8 KB |
swapfile.c | -rw-r--r-- | 84.4 KB |
truncate.c | -rw-r--r-- | 24.9 KB |
usercopy.c | -rw-r--r-- | 7.8 KB |
userfaultfd.c | -rw-r--r-- | 14.3 KB |
util.c | -rw-r--r-- | 16.0 KB |
vmacache.c | -rw-r--r-- | 3.2 KB |
vmalloc.c | -rw-r--r-- | 69.4 KB |
vmpressure.c | -rw-r--r-- | 12.7 KB |
vmscan.c | -rw-r--r-- | 111.7 KB |
vmstat.c | -rw-r--r-- | 47.3 KB |
workingset.c | -rw-r--r-- | 18.2 KB |
z3fold.c | -rw-r--r-- | 23.6 KB |
zbud.c | -rw-r--r-- | 18.2 KB |
zpool.c | -rw-r--r-- | 10.0 KB |
zsmalloc.c | -rw-r--r-- | 59.3 KB |
zswap.c | -rw-r--r-- | 32.8 KB |
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