fuse: fix memleak in cuse_channel_open

BugLink: https://bugs.launchpad.net/bugs/1848780

[ Upstream commit 9ad09b19 ]

If cuse_send_init fails, need to fuse_conn_put cc->fc.

cuse_channel_open->fuse_conn_init->refcount_set(&fc->count, 1)
                 ->fuse_dev_alloc->fuse_conn_get
                 ->fuse_dev_free->fuse_conn_put

Fixes: cc080e9e ("fuse: introduce per-instance fuse_dev structure")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

fs/fuse/cuse.c

@@ -514,6 +514,7 @@ static int cuse_channel_open(struct inode *inode, struct file *file)
 	rc = cuse_send_init(cc);
 	if (rc) {
 		fuse_dev_free(fud);
+		fuse_conn_put(&cc->fc);
 		return rc;
 	}
 	file->private_data = fud;