4.20-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jann Horn <jannh@xxxxxxxxxx>
commit 9509941e9c534920ccc4771ae70bd6cbbe79df1c upstream.
Some of the pipe_buf_release() handlers seem to assume that the pipe is
locked - in particular, anon_pipe_buf_release() accesses pipe->tmp_page
without taking any extra locks. From a glance through the callers of
pipe_buf_release(), it looks like FUSE is the only one that calls
pipe_buf_release() without having the pipe locked.
This bug should only lead to a memory leak, nothing terrible.
Fixes: dd3bb14f44a6 ("fuse: support splice() writing to fuse device")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/fuse/dev.c | 2 ++
1 file changed, 2 insertions(+)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -2077,8 +2077,10 @@ static ssize_t fuse_dev_splice_write(str
ret = fuse_dev_do_write(fud, &cs, len);
+ pipe_lock(pipe);
for (idx = 0; idx < nbuf; idx++)
pipe_buf_release(pipe, &bufs[idx]);
+ pipe_unlock(pipe);
out:
kvfree(bufs);
