| From | Sasha Levin <> | Subject | [PATCH AUTOSEL 4.19 166/206] fuse: don't check refcount after stealing page | Date | Thu, 17 Sep 2020 22:07:22 -0400 |
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From: Miklos Szeredi <mszeredi@redhat.com>
[ Upstream commit 32f98877c57bee6bc27f443a96f49678a2cd6a50 ]
page_count() is unstable. Unless there has been an RCU grace period between when the page was removed from the page cache and now, a speculative reference may exist from the page cache.
Reported-by: Matthew Wilcox <willy@infradead.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- fs/fuse/dev.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 01e6ea11822bf..c51c9a6881e49 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -831,7 +831,6 @@ static int fuse_check_page(struct page *page) { if (page_mapcount(page) || page->mapping != NULL || - page_count(page) != 1 || (page->flags & PAGE_FLAGS_CHECK_AT_PREP & ~(1 << PG_locked | 1 << PG_referenced | -- 2.25.1
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