Hello Hou Pu,
This is a semi-automatic email about new static checker warnings.
The patch 2c272542baee: "nbd: requeue command if the soecket is
changed" from Feb 28, 2020, leads to the following Smatch complaint:
drivers/block/nbd.c:437 nbd_xmit_timeout()
error: we previously assumed 'config->socks' could be null (see line 410)
drivers/block/nbd.c
409 */
410 if (config->socks) {
^^^^^^^^^^^^^
Check for NULL.
411 if (cmd->index < config->num_connections) {
412 struct nbd_sock *nsock =
413 config->socks[cmd->index];
414 mutex_lock(&nsock->tx_lock);
415 /* We can have multiple outstanding requests, so
416 * we don't want to mark the nsock dead if we've
417 * already reconnected with a new socket, so
418 * only mark it dead if its the same socket we
419 * were sent out on.
420 */
421 if (cmd->cookie == nsock->cookie)
422 nbd_mark_nsock_dead(nbd, nsock, 1);
423 mutex_unlock(&nsock->tx_lock);
424 }
425 mutex_unlock(&cmd->lock);
426 nbd_requeue_cmd(cmd);
427 nbd_config_put(nbd);
428 return BLK_EH_DONE;
429 }
430 }
431
432 if (!nbd->tag_set.timeout) {
433 /*
434 * Userspace sets timeout=0 to disable socket disconnection,
435 * so just warn and reset the timer.
436 */
437 struct nbd_sock *nsock = config->socks[cmd->index];
^^^^^^^^^^^^^
New unchecked dereference.
Also on the other path, we check that "cmd->index" is within bounds but
here we just assume that it is.
438 cmd->retries++;
439 dev_info(nbd_to_dev(nbd), "Possible stuck request %p: control (%s@%llu,%uB). Runtime %u seconds\n",
regards,
dan carpenter
