hv_sock: Initializing vsk->trans to NULL to prevent a dangling pointer

commit e629295 upstream.

When hvs is released, there is a possibility that vsk->trans may not
be initialized to NULL, which could lead to a dangling pointer.
This issue is resolved by initializing vsk->trans to NULL.

Signed-off-by: Hyunwoo Kim <[email protected]>
Reviewed-by: Stefano Garzarella <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Link: https://patch.msgid.link/Zys4hCj61V+mQfX2@v4bel-B760M-AORUS-ELITE-AX
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

net/vmw_vsock/hyperv_transport.c

@@ -549,6 +549,7 @@ static void hvs_destruct(struct vsock_sock *vsk)
 		vmbus_hvsock_device_unregister(chan);
 
 	kfree(hvs);
+	vsk->trans = NULL;
 }
 
 static int hvs_dgram_bind(struct vsock_sock *vsk, struct sockaddr_vm *addr)