From: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> This patch has been added to the 3.12 stable tree. If you have any objections, please let us know. =============== commit 09789e5de18e4e442870b2d700831f5cb802eb05 upstream. Currently memory_failure() calls shake_page() to sweep pages out from pcplists only when the victim page is 4kB LRU page or thp head page. But we should do this for a thp tail page too. Consider that a memory error hits a thp tail page whose head page is on a pcplist when memory_failure() runs. Then, the current kernel skips shake_pages() part, so hwpoison_user_mappings() returns without calling split_huge_page() nor try_to_unmap() because PageLRU of the thp head is still cleared due to the skip of shake_page(). As a result, me_huge_page() runs for the thp, which is broken behavior. One effect is a leak of the thp. And another is to fail to isolate the memory error, so later access to the error address causes another MCE, which kills the processes which used the thp. This patch fixes this problem by calling shake_page() for thp tail case. Fixes: 385de35722c9 ("thp: allow a hwpoisoned head page to be put back to LRU") Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx> Acked-by: Dean Nelson <dnelson@xxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx> Cc: Jin Dongming <jin.dongming@xxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx> --- mm/memory-failure.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 532b4661985c..2e94ad1133af 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1149,10 +1149,10 @@ int memory_failure(unsigned long pfn, int trapno, int flags) * The check (unnecessarily) ignores LRU pages being isolated and * walked by the page reclaim code, however that's not a big loss. */ - if (!PageHuge(p) && !PageTransTail(p)) { - if (!PageLRU(p)) - shake_page(p, 0); - if (!PageLRU(p)) { + if (!PageHuge(p)) { + if (!PageLRU(hpage)) + shake_page(hpage, 0); + if (!PageLRU(hpage)) { /* * shake_page could have turned it free. */ -- 2.3.7 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html