fuse: fix leaked notify reply

BugLink: https://bugs.launchpad.net/bugs/1824553
fuse_request_send_notify_reply() may fail if the connection was reset for
some reason (e.g. fs was unmounted).  Don't leak request reference in this
case.  Besides leaking memory, this resulted in fc->num_waiting not being
decremented and hence fuse_wait_aborted() left in a hanging and unkillable
state.

Fixes: 2d45ba381a74 ("fuse: add retrieve request")
Fixes: b8f95e5d13f5 ("fuse: umount should wait for all requests")
Reported-and-tested-by: syzbot+6339eda9cb4ebbc4c37b@syzkaller.appspotmail.com
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: <stable@vger.kernel.org> #v2.6.36
(cherry picked from commit 7fabaf303458fcabb694999d6fa772cc13d4e217)
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 7bb09742b3f9d11a506999c6abe375b1809a0bd0..0ad5c49f9a5b43f0427b00ea7a846046969b877c 100644 (file)
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -1728,8 +1728,10 @@ static int fuse_retrieve(struct fuse_conn *fc, struct inode *inode,
        req->in.args[1].size = total_len;
 
        err = fuse_request_send_notify_reply(fc, req, outarg->notify_unique);
-       if (err)
+       if (err) {
                fuse_retrieve_end(fc, req);
+               fuse_put_request(fc, req);
+       }
 
        return err;
 }