4.20-stable review patch. If anyone has any objections, please let me know.
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From: Jann Horn jannh@google.com
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@vger.kernel.org Signed-off-by: Jann Horn jannh@google.com Signed-off-by: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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);