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authorMatthew Wilcox (Oracle) <willy@infradead.org>2021-11-05 13:37:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 13:30:34 -0700
commitd417b49fff3e2f21043c834841e8623a6098741d (patch)
tree86ea2d7cbe7b558b4f96da5821274a88f578592d
parent61d0017e5a32d3b13ba3c7becc83a5a9e53cdbe9 (diff)
mm/filemap.c: remove bogus VM_BUG_ON
It is not safe to check page->index without holding the page lock. It can be changed if the page is moved between the swap cache and the page cache for a shmem file, for example. There is a VM_BUG_ON below which checks page->index is correct after taking the page lock. Link: https://lkml.kernel.org/r/20210818144932.940640-1-willy@infradead.org Fixes: 5c211ba29deb ("mm: add and use find_lock_entries") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reported-by: <syzbot+c87be4f669d920c76330@syzkaller.appspotmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/filemap.c1
1 files changed, 0 insertions, 1 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index ebd68890a844..28c57c2536d0 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2093,7 +2093,6 @@ unsigned find_lock_entries(struct address_space *mapping, pgoff_t start,
if (!xa_is_value(page)) {
if (page->index < start)
goto put;
- VM_BUG_ON_PAGE(page->index != xas.xa_index, page);
if (page->index + thp_nr_pages(page) - 1 > end)
goto put;
if (!trylock_page(page))