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authorNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>2016-11-10 21:46:23 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-11-11 19:12:37 +0300
commitc3901e722b2975666f42748340df798114742d6d (patch)
tree9cd4508bd975e35b393982f3c61101c98c90dee6 /mm/memory-failure.c
parentdd111be69114cc867f8e826284559bfbc1c40e37 (diff)
downloadlinux-c3901e722b2975666f42748340df798114742d6d.tar.xz
mm: hwpoison: fix thp split handling in memory_failure()
When memory_failure() runs on a thp tail page after pmd is split, we trigger the following VM_BUG_ON_PAGE(): page:ffffd7cd819b0040 count:0 mapcount:0 mapping: (null) index:0x1 flags: 0x1fffc000400000(hwpoison) page dumped because: VM_BUG_ON_PAGE(!page_count(p)) ------------[ cut here ]------------ kernel BUG at /src/linux-dev/mm/memory-failure.c:1132! memory_failure() passed refcount and page lock from tail page to head page, which is not needed because we can pass any subpage to split_huge_page(). Fixes: 61f5d698cc97 ("mm: re-enable THP") Link: http://lkml.kernel.org/r/1477961577-7183-1-git-send-email-n-horiguchi@ah.jp.nec.com Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: <stable@vger.kernel.org> [4.5+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory-failure.c')
-rw-r--r--mm/memory-failure.c12
1 files changed, 5 insertions, 7 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index de88f33519c0..19e796d36a62 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1112,10 +1112,10 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
}
if (!PageHuge(p) && PageTransHuge(hpage)) {
- lock_page(hpage);
- if (!PageAnon(hpage) || unlikely(split_huge_page(hpage))) {
- unlock_page(hpage);
- if (!PageAnon(hpage))
+ lock_page(p);
+ if (!PageAnon(p) || unlikely(split_huge_page(p))) {
+ unlock_page(p);
+ if (!PageAnon(p))
pr_err("Memory failure: %#lx: non anonymous thp\n",
pfn);
else
@@ -1126,9 +1126,7 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
put_hwpoison_page(p);
return -EBUSY;
}
- unlock_page(hpage);
- get_hwpoison_page(p);
- put_hwpoison_page(hpage);
+ unlock_page(p);
VM_BUG_ON_PAGE(!page_count(p), p);
hpage = compound_head(p);
}