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authorMinchan Kim <minchan@kernel.org>2017-05-03 14:52:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-05-03 15:52:08 -0700
commiteb94a8784427b28479f871b5d4121c547808d0fc (patch)
treec888f13dc71e13ea4a832598fc06cc325142373b /mm/rmap.c
parent802a3a92ad7ac0b9be9df229dee530a1f0a8039b (diff)
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mm: fix lazyfree BUG_ON check in try_to_unmap_one()
If a page is swapbacked, it means it should be in swapcache in try_to_unmap_one's path. If a page is !swapbacked, it mean it shouldn't be in swapcache in try_to_unmap_one's path. Check both two cases all at once and if it fails, warn and return SWAP_FAIL. Such bug never mean we should shut down the kernel. [minchan@kernel.org: do not use VM_WARN_ON_ONCE as if condition[ Link: http://lkml.kernel.org/r/20170309060226.GB854@bbox Link: http://lkml.kernel.org/r/20170307055551.GC29458@bbox Signed-off-by: Minchan Kim <minchan@kernel.org> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Shaohua Li <shli@fb.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/rmap.c')
-rw-r--r--mm/rmap.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 519b7eb723d1..a19bd8b8ab0d 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1418,8 +1418,12 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
* Store the swap location in the pte.
* See handle_pte_fault() ...
*/
- VM_BUG_ON_PAGE(!PageSwapCache(page) && PageSwapBacked(page),
- page);
+ if (unlikely(PageSwapBacked(page) != PageSwapCache(page))) {
+ WARN_ON_ONCE(1);
+ ret = SWAP_FAIL;
+ page_vma_mapped_walk_done(&pvmw);
+ break;
+ }
/* MADV_FREE page check */
if (!PageSwapBacked(page)) {