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| author | Miaohe Lin <linmiaohe@huawei.com> | 2022-03-22 14:44:44 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-07-12 16:35:05 +0200 |
| commit | 5429eb5502fc7e64abdb3a4f6b9f698a8337da5d (patch) | |
| tree | e046a81252e81847d90c86b976f9f75a5f4ab289 /mm | |
| parent | 7a07875fabccc17c4564151c19de2174948d0544 (diff) | |
| download | linux-5429eb5502fc7e64abdb3a4f6b9f698a8337da5d.tar.gz linux-5429eb5502fc7e64abdb3a4f6b9f698a8337da5d.tar.bz2 linux-5429eb5502fc7e64abdb3a4f6b9f698a8337da5d.zip | |
mm/memory-failure.c: fix race with changing page compound again
[ Upstream commit 888af2701db79b9b27c7e37f9ede528a5ca53b76 ]
Patch series "A few fixup patches for memory failure", v2.
This series contains a few patches to fix the race with changing page
compound page, make non-LRU movable pages unhandlable and so on. More
details can be found in the respective changelogs.
There is a race window where we got the compound_head, the hugetlb page
could be freed to buddy, or even changed to another compound page just
before we try to get hwpoison page. Think about the below race window:
CPU 1 CPU 2
memory_failure_hugetlb
struct page *head = compound_head(p);
hugetlb page might be freed to
buddy, or even changed to another
compound page.
get_hwpoison_page -- page is not what we want now...
If this race happens, just bail out. Also MF_MSG_DIFFERENT_PAGE_SIZE is
introduced to record this event.
[akpm@linux-foundation.org: s@/**@/*@, per Naoya Horiguchi]
Link: https://lkml.kernel.org/r/20220312074613.4798-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20220312074613.4798-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory-failure.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 5664bafd5e77..a4d70c21c146 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -741,6 +741,7 @@ static const char * const action_page_types[] = { [MF_MSG_BUDDY_2ND] = "free buddy page (2nd try)", [MF_MSG_DAX] = "dax page", [MF_MSG_UNSPLIT_THP] = "unsplit thp", + [MF_MSG_DIFFERENT_PAGE_SIZE] = "different page size", [MF_MSG_UNKNOWN] = "unknown page", }; @@ -1461,6 +1462,17 @@ static int memory_failure_hugetlb(unsigned long pfn, int flags) } lock_page(head); + + /* + * The page could have changed compound pages due to race window. + * If this happens just bail out. + */ + if (!PageHuge(p) || compound_head(p) != head) { + action_result(pfn, MF_MSG_DIFFERENT_PAGE_SIZE, MF_IGNORED); + res = -EBUSY; + goto out; + } + page_flags = head->flags; /* |