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| author | Miaohe Lin <linmiaohe@huawei.com> | 2022-03-22 14:44:44 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-22 15:57:07 -0700 |
| commit | 888af2701db79b9b27c7e37f9ede528a5ca53b76 (patch) | |
| tree | 407681cc93ae20b77e553816228978e38c2cb132 /mm/memory-failure.c | |
| parent | a06ad3c0c75297f0b0999b1a981e50224e690ee9 (diff) | |
| download | linux-888af2701db79b9b27c7e37f9ede528a5ca53b76.tar.gz | |
mm/memory-failure.c: fix race with changing page compound again
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>
Diffstat (limited to 'mm/memory-failure.c')
| -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 086ae4eb3421..7ec855149393 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -732,6 +732,7 @@ static const char * const action_page_types[] = { [MF_MSG_BUDDY] = "free buddy page", [MF_MSG_DAX] = "dax page", [MF_MSG_UNSPLIT_THP] = "unsplit thp", + [MF_MSG_DIFFERENT_PAGE_SIZE] = "different page size", [MF_MSG_UNKNOWN] = "unknown page", }; @@ -1532,6 +1533,17 @@ 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; if (hwpoison_filter(p)) { |