diff options
| 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 | |
| parent | mm/hwpoison: add in-use hugepage hwpoison filter judgement (diff) | |
| download | wireguard-linux-888af2701db79b9b27c7e37f9ede528a5ca53b76.tar.xz wireguard-linux-888af2701db79b9b27c7e37f9ede528a5ca53b76.zip | |
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>
| -rw-r--r-- | include/linux/mm.h | 1 | ||||
| -rw-r--r-- | include/ras/ras_event.h | 1 | ||||
| -rw-r--r-- | mm/memory-failure.c | 12 |
3 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index d0978235775f..45a449e8c209 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3239,6 +3239,7 @@ enum mf_action_page_type { MF_MSG_BUDDY, MF_MSG_DAX, MF_MSG_UNSPLIT_THP, + MF_MSG_DIFFERENT_PAGE_SIZE, MF_MSG_UNKNOWN, }; diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h index d0337a41141c..1e694fd239b9 100644 --- a/include/ras/ras_event.h +++ b/include/ras/ras_event.h @@ -374,6 +374,7 @@ TRACE_EVENT(aer_event, EM ( MF_MSG_BUDDY, "free buddy page" ) \ EM ( MF_MSG_DAX, "dax page" ) \ EM ( MF_MSG_UNSPLIT_THP, "unsplit thp" ) \ + EM ( MF_MSG_DIFFERENT_PAGE_SIZE, "different page size" ) \ EMe ( MF_MSG_UNKNOWN, "unknown page" ) /* 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)) { |