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authorMiklos Szeredi <mszeredi@redhat.com>2021-11-25 14:05:18 +0100
committerMiklos Szeredi <mszeredi@redhat.com>2021-11-25 14:05:18 +0100
commit473441720c8616dfaf4451f9c7ea14f0eb5e5d65 (patch)
treec0f5f1f848288b5015ccd4dbc5c5c965386b18ad /fs
parentfa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf (diff)
downloadlinux-473441720c8616dfaf4451f9c7ea14f0eb5e5d65.tar.gz
fuse: release pipe buf after last use
Checking buf->flags should be done before the pipe_buf_release() is called
on the pipe buffer, since releasing the buffer might modify the flags.

This is exactly what page_cache_pipe_buf_release() does, and which results
in the same VM_BUG_ON_PAGE(PageLRU(page)) that the original patch was
trying to fix.

Reported-by: Justin Forbes <jmforbes@linuxtx.org>
Fixes: 712a951025c0 ("fuse: fix page stealing")
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/fuse/dev.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 79f7eda49e06..cd54a529460d 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -847,17 +847,17 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 
 	replace_page_cache_page(oldpage, newpage);
 
+	get_page(newpage);
+
+	if (!(buf->flags & PIPE_BUF_FLAG_LRU))
+		lru_cache_add(newpage);
+
 	/*
 	 * Release while we have extra ref on stolen page.  Otherwise
 	 * anon_pipe_buf_release() might think the page can be reused.
 	 */
 	pipe_buf_release(cs->pipe, buf);
 
-	get_page(newpage);
-
-	if (!(buf->flags & PIPE_BUF_FLAG_LRU))
-		lru_cache_add(newpage);
-
 	err = 0;
 	spin_lock(&cs->req->waitq.lock);
 	if (test_bit(FR_ABORTED, &cs->req->flags))