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authorNaoya Horiguchi <naoya.horiguchi@nec.com>2022-04-21 16:35:33 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-04-21 20:01:09 -0700
commit405ce051236cc65b30bbfe490b28ce60ae6aed85 (patch)
treed89d8b57f42342501b361d98590b13fb1ecc5cac /include/linux/hugetlb.h
parentb253435746d9a4a701b5f09211b9c14d3370d0da (diff)
mm/hwpoison: fix race between hugetlb free/demotion and memory_failure_hugetlb()
There is a race condition between memory_failure_hugetlb() and hugetlb free/demotion, which causes setting PageHWPoison flag on the wrong page. The one simple result is that wrong processes can be killed, but another (more serious) one is that the actual error is left unhandled, so no one prevents later access to it, and that might lead to more serious results like consuming corrupted data. 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... The current code first does prechecks roughly and then reconfirms after taking refcount, but it's found that it makes code overly complicated, so move the prechecks in a single hugetlb_lock range. A newly introduced function, try_memory_failure_hugetlb(), always takes hugetlb_lock (even for non-hugetlb pages). That can be improved, but memory_failure() is rare in principle, so should not be a big problem. Link: https://lkml.kernel.org/r/20220408135323.1559401-2-naoya.horiguchi@linux.dev Fixes: 761ad8d7c7b5 ("mm: hwpoison: introduce memory_failure_hugetlb()") Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Reported-by: Mike Kravetz <mike.kravetz@oracle.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Yang Shi <shy828301@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/hugetlb.h')
-rw-r--r--include/linux/hugetlb.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 53c1b6082a4c..ac2a1d758a80 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -169,6 +169,7 @@ long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
long freed);
bool isolate_huge_page(struct page *page, struct list_head *list);
int get_hwpoison_huge_page(struct page *page, bool *hugetlb);
+int get_huge_page_for_hwpoison(unsigned long pfn, int flags);
void putback_active_hugepage(struct page *page);
void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason);
void free_huge_page(struct page *page);
@@ -378,6 +379,11 @@ static inline int get_hwpoison_huge_page(struct page *page, bool *hugetlb)
return 0;
}
+static inline int get_huge_page_for_hwpoison(unsigned long pfn, int flags)
+{
+ return 0;
+}
+
static inline void putback_active_hugepage(struct page *page)
{
}