From: Miklos Szeredi Date: Tue, 19 May 2020 12:50:37 +0000 (+0200) Subject: fuse: don't check refcount after stealing page X-Git-Tag: v4.4.238~25 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1cec5992cc34aa082541ff10b0ba0356e1e3c045;p=thirdparty%2Fkernel%2Fstable.git fuse: don't check refcount after stealing page [ 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 Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin --- diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index 8142f6bf3d310..fc265f4b839ae 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -850,7 +850,6 @@ 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 |