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author | Andrea Arcangeli <aarcange@redhat.com> | 2011-01-13 23:46:33 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-14 01:32:39 (GMT) |
commit | a95a82e96c48270980dd248ccd5546f1b49e6f8a (patch) | |
tree | 35f10c2a8d2cd0e1aa9d33f7a4f55332c0733ee6 | |
parent | 9180706344487700b40da9eca5dedd3d11cb33b4 (diff) | |
download | linux-fsl-qoriq-a95a82e96c48270980dd248ccd5546f1b49e6f8a.tar.xz |
thp: put_page: recheck PageHead after releasing the compound_lock
After releasing the compound_lock split_huge_page can still run and release the
page before put_page_testzero runs.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | mm/swap.c | 8 |
1 files changed, 6 insertions, 2 deletions
@@ -131,8 +131,12 @@ static void put_compound_page(struct page *page) atomic_dec(&page->_count); VM_BUG_ON(atomic_read(&page_head->_count) <= 0); compound_unlock_irqrestore(page_head, flags); - if (put_page_testzero(page_head)) - __put_compound_page(page_head); + if (put_page_testzero(page_head)) { + if (PageHead(page_head)) + __put_compound_page(page_head); + else + __put_single_page(page_head); + } } else { /* page_head is a dangling pointer */ VM_BUG_ON(PageTail(page)); |