===== =====
__sock_release virtio_transport_recv_pkt
__vsock_release vsock_find_bound_socket (found)
lock_sock_nested
vsock_remove_sock
sock_orphan
sk_set_socket(sk, NULL)
...
release_sock
lock_sock
virtio_transport_recv_connecting
sk->sk_socket->state (panic)
The root cause is that vsock_find_bound_socket can't hold the lock_sock,
so there is a small race window between vsock_find_bound_socket() and
lock_sock(). If there is __vsock_release() in another task, sk->sk_socket
will be set to NULL inadvertently.
This fixes it by checking sk->sk_shutdown.
Signed-off-by: Jia He <justin.he@arm.com>
Cc: stable@vger.kernel.org
Cc: Stefano Garzarella <sgarzare@redhat.com>
---
v2: use lightweight checking suggested by Stefano Garzarella
net/vmw_vsock/virtio_transport_common.c | 8 ++++++++
1 file changed, 8 insertions(+)
@@ -1132,6 +1132,14 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
lock_sock(sk);
+ /* Check if sk has been released before lock_sock */
+ if (sk->sk_shutdown == SHUTDOWN_MASK) {
+ (void)virtio_transport_reset_no_sock(t, pkt);
+ release_sock(sk);
+ sock_put(sk);
+ goto free_pkt;
+ }
+
/* Update CID in case it has changed after a transport reset event */
vsk->local_addr.svm_cid = dst.svm_cid;