From: Tyrel Datwyler <tyreld@xxxxxxxxxxxxx> [ Upstream commit b39f2d10b86d0af353ea339e5815820026bca48f ] In practice the driver should never send more commands than are allocated to a queue's event pool. In the unlikely event that this happens, the code asserts a BUG_ON, and in the case that the kernel is not configured to crash on panic returns a junk event pointer from the empty event list causing things to spiral from there. This BUG_ON is a historical artifact of the ibmvfc driver first being upstreamed, and it is well known now that the use of BUG_ON is bad practice except in the most unrecoverable scenario. There is nothing about this scenario that prevents the driver from recovering and carrying on. Remove the BUG_ON in question from ibmvfc_get_event() and return a NULL pointer in the case of an empty event pool. Update all call sites to ibmvfc_get_event() to check for a NULL pointer and perfrom the appropriate failure or recovery action. Signed-off-by: Tyrel Datwyler <tyreld@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20230921225435.3537728-2-tyreld@xxxxxxxxxxxxx Reviewed-by: Brian King <brking@xxxxxxxxxxxxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/scsi/ibmvscsi/ibmvfc.c | 124 ++++++++++++++++++++++++++++++++- 1 file changed, 122 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c index 45ef78f388dc9..e1895686987f0 100644 --- a/drivers/scsi/ibmvscsi/ibmvfc.c +++ b/drivers/scsi/ibmvscsi/ibmvfc.c @@ -1519,7 +1519,11 @@ static struct ibmvfc_event *ibmvfc_get_event(struct ibmvfc_queue *queue) unsigned long flags; spin_lock_irqsave(&queue->l_lock, flags); - BUG_ON(list_empty(&queue->free)); + if (list_empty(&queue->free)) { + ibmvfc_log(queue->vhost, 4, "empty event pool on queue:%ld\n", queue->hwq_id); + spin_unlock_irqrestore(&queue->l_lock, flags); + return NULL; + } evt = list_entry(queue->free.next, struct ibmvfc_event, queue_list); atomic_set(&evt->free, 0); list_del(&evt->queue_list); @@ -1948,9 +1952,15 @@ static int ibmvfc_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *cmnd) if (vhost->using_channels) { scsi_channel = hwq % vhost->scsi_scrqs.active_queues; evt = ibmvfc_get_event(&vhost->scsi_scrqs.scrqs[scsi_channel]); + if (!evt) + return SCSI_MLQUEUE_HOST_BUSY; + evt->hwq = hwq % vhost->scsi_scrqs.active_queues; - } else + } else { evt = ibmvfc_get_event(&vhost->crq); + if (!evt) + return SCSI_MLQUEUE_HOST_BUSY; + } ibmvfc_init_event(evt, ibmvfc_scsi_done, IBMVFC_CMD_FORMAT); evt->cmnd = cmnd; @@ -2038,6 +2048,11 @@ static int ibmvfc_bsg_timeout(struct bsg_job *job) vhost->aborting_passthru = 1; evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + spin_unlock_irqrestore(vhost->host->host_lock, flags); + return -ENOMEM; + } + ibmvfc_init_event(evt, ibmvfc_bsg_timeout_done, IBMVFC_MAD_FORMAT); tmf = &evt->iu.tmf; @@ -2096,6 +2111,10 @@ static int ibmvfc_bsg_plogi(struct ibmvfc_host *vhost, unsigned int port_id) goto unlock_out; evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + rc = -ENOMEM; + goto unlock_out; + } ibmvfc_init_event(evt, ibmvfc_sync_completion, IBMVFC_MAD_FORMAT); plogi = &evt->iu.plogi; memset(plogi, 0, sizeof(*plogi)); @@ -2214,6 +2233,11 @@ static int ibmvfc_bsg_request(struct bsg_job *job) } evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + spin_unlock_irqrestore(vhost->host->host_lock, flags); + rc = -ENOMEM; + goto out; + } ibmvfc_init_event(evt, ibmvfc_sync_completion, IBMVFC_MAD_FORMAT); mad = &evt->iu.passthru; @@ -2302,6 +2326,11 @@ static int ibmvfc_reset_device(struct scsi_device *sdev, int type, char *desc) else evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + spin_unlock_irqrestore(vhost->host->host_lock, flags); + return -ENOMEM; + } + ibmvfc_init_event(evt, ibmvfc_sync_completion, IBMVFC_CMD_FORMAT); tmf = ibmvfc_init_vfc_cmd(evt, sdev); iu = ibmvfc_get_fcp_iu(vhost, tmf); @@ -2505,6 +2534,8 @@ static struct ibmvfc_event *ibmvfc_init_tmf(struct ibmvfc_queue *queue, struct ibmvfc_tmf *tmf; evt = ibmvfc_get_event(queue); + if (!evt) + return NULL; ibmvfc_init_event(evt, ibmvfc_sync_completion, IBMVFC_MAD_FORMAT); tmf = &evt->iu.tmf; @@ -2561,6 +2592,11 @@ static int ibmvfc_cancel_all_mq(struct scsi_device *sdev, int type) if (found_evt && vhost->logged_in) { evt = ibmvfc_init_tmf(&queues[i], sdev, type); + if (!evt) { + spin_unlock(queues[i].q_lock); + spin_unlock_irqrestore(vhost->host->host_lock, flags); + return -ENOMEM; + } evt->sync_iu = &queues[i].cancel_rsp; ibmvfc_send_event(evt, vhost, default_timeout); list_add_tail(&evt->cancel, &cancelq); @@ -2774,6 +2810,10 @@ static int ibmvfc_abort_task_set(struct scsi_device *sdev) if (vhost->state == IBMVFC_ACTIVE) { evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + spin_unlock_irqrestore(vhost->host->host_lock, flags); + return -ENOMEM; + } ibmvfc_init_event(evt, ibmvfc_sync_completion, IBMVFC_CMD_FORMAT); tmf = ibmvfc_init_vfc_cmd(evt, sdev); iu = ibmvfc_get_fcp_iu(vhost, tmf); @@ -4030,6 +4070,12 @@ static void ibmvfc_tgt_send_prli(struct ibmvfc_target *tgt) kref_get(&tgt->kref); evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + ibmvfc_set_tgt_action(tgt, IBMVFC_TGT_ACTION_NONE); + kref_put(&tgt->kref, ibmvfc_release_tgt); + __ibmvfc_reset_host(vhost); + return; + } vhost->discovery_threads++; ibmvfc_init_event(evt, ibmvfc_tgt_prli_done, IBMVFC_MAD_FORMAT); evt->tgt = tgt; @@ -4137,6 +4183,12 @@ static void ibmvfc_tgt_send_plogi(struct ibmvfc_target *tgt) kref_get(&tgt->kref); tgt->logo_rcvd = 0; evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + ibmvfc_set_tgt_action(tgt, IBMVFC_TGT_ACTION_NONE); + kref_put(&tgt->kref, ibmvfc_release_tgt); + __ibmvfc_reset_host(vhost); + return; + } vhost->discovery_threads++; ibmvfc_set_tgt_action(tgt, IBMVFC_TGT_ACTION_INIT_WAIT); ibmvfc_init_event(evt, ibmvfc_tgt_plogi_done, IBMVFC_MAD_FORMAT); @@ -4213,6 +4265,8 @@ static struct ibmvfc_event *__ibmvfc_tgt_get_implicit_logout_evt(struct ibmvfc_t kref_get(&tgt->kref); evt = ibmvfc_get_event(&vhost->crq); + if (!evt) + return NULL; ibmvfc_init_event(evt, done, IBMVFC_MAD_FORMAT); evt->tgt = tgt; mad = &evt->iu.implicit_logout; @@ -4240,6 +4294,13 @@ static void ibmvfc_tgt_implicit_logout(struct ibmvfc_target *tgt) vhost->discovery_threads++; evt = __ibmvfc_tgt_get_implicit_logout_evt(tgt, ibmvfc_tgt_implicit_logout_done); + if (!evt) { + vhost->discovery_threads--; + ibmvfc_set_tgt_action(tgt, IBMVFC_TGT_ACTION_NONE); + kref_put(&tgt->kref, ibmvfc_release_tgt); + __ibmvfc_reset_host(vhost); + return; + } ibmvfc_set_tgt_action(tgt, IBMVFC_TGT_ACTION_INIT_WAIT); if (ibmvfc_send_event(evt, vhost, default_timeout)) { @@ -4379,6 +4440,12 @@ static void ibmvfc_tgt_move_login(struct ibmvfc_target *tgt) kref_get(&tgt->kref); evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + ibmvfc_set_tgt_action(tgt, IBMVFC_TGT_ACTION_DEL_RPORT); + kref_put(&tgt->kref, ibmvfc_release_tgt); + __ibmvfc_reset_host(vhost); + return; + } vhost->discovery_threads++; ibmvfc_set_tgt_action(tgt, IBMVFC_TGT_ACTION_INIT_WAIT); ibmvfc_init_event(evt, ibmvfc_tgt_move_login_done, IBMVFC_MAD_FORMAT); @@ -4545,6 +4612,14 @@ static void ibmvfc_adisc_timeout(struct timer_list *t) vhost->abort_threads++; kref_get(&tgt->kref); evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + tgt_err(tgt, "Failed to get cancel event for ADISC.\n"); + vhost->abort_threads--; + kref_put(&tgt->kref, ibmvfc_release_tgt); + __ibmvfc_reset_host(vhost); + spin_unlock_irqrestore(vhost->host->host_lock, flags); + return; + } ibmvfc_init_event(evt, ibmvfc_tgt_adisc_cancel_done, IBMVFC_MAD_FORMAT); evt->tgt = tgt; @@ -4595,6 +4670,12 @@ static void ibmvfc_tgt_adisc(struct ibmvfc_target *tgt) kref_get(&tgt->kref); evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + ibmvfc_set_tgt_action(tgt, IBMVFC_TGT_ACTION_NONE); + kref_put(&tgt->kref, ibmvfc_release_tgt); + __ibmvfc_reset_host(vhost); + return; + } vhost->discovery_threads++; ibmvfc_init_event(evt, ibmvfc_tgt_adisc_done, IBMVFC_MAD_FORMAT); evt->tgt = tgt; @@ -4698,6 +4779,12 @@ static void ibmvfc_tgt_query_target(struct ibmvfc_target *tgt) kref_get(&tgt->kref); evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + ibmvfc_set_tgt_action(tgt, IBMVFC_TGT_ACTION_NONE); + kref_put(&tgt->kref, ibmvfc_release_tgt); + __ibmvfc_reset_host(vhost); + return; + } vhost->discovery_threads++; evt->tgt = tgt; ibmvfc_init_event(evt, ibmvfc_tgt_query_target_done, IBMVFC_MAD_FORMAT); @@ -4870,6 +4957,13 @@ static void ibmvfc_discover_targets(struct ibmvfc_host *vhost) { struct ibmvfc_discover_targets *mad; struct ibmvfc_event *evt = ibmvfc_get_event(&vhost->crq); + int level = IBMVFC_DEFAULT_LOG_LEVEL; + + if (!evt) { + ibmvfc_log(vhost, level, "Discover Targets failed: no available events\n"); + ibmvfc_hard_reset_host(vhost); + return; + } ibmvfc_init_event(evt, ibmvfc_discover_targets_done, IBMVFC_MAD_FORMAT); mad = &evt->iu.discover_targets; @@ -4947,8 +5041,15 @@ static void ibmvfc_channel_setup(struct ibmvfc_host *vhost) struct ibmvfc_scsi_channels *scrqs = &vhost->scsi_scrqs; unsigned int num_channels = min(vhost->client_scsi_channels, vhost->max_vios_scsi_channels); + int level = IBMVFC_DEFAULT_LOG_LEVEL; int i; + if (!evt) { + ibmvfc_log(vhost, level, "Channel Setup failed: no available events\n"); + ibmvfc_hard_reset_host(vhost); + return; + } + memset(setup_buf, 0, sizeof(*setup_buf)); if (num_channels == 0) setup_buf->flags = cpu_to_be32(IBMVFC_CANCEL_CHANNELS); @@ -5010,6 +5111,13 @@ static void ibmvfc_channel_enquiry(struct ibmvfc_host *vhost) { struct ibmvfc_channel_enquiry *mad; struct ibmvfc_event *evt = ibmvfc_get_event(&vhost->crq); + int level = IBMVFC_DEFAULT_LOG_LEVEL; + + if (!evt) { + ibmvfc_log(vhost, level, "Channel Enquiry failed: no available events\n"); + ibmvfc_hard_reset_host(vhost); + return; + } ibmvfc_init_event(evt, ibmvfc_channel_enquiry_done, IBMVFC_MAD_FORMAT); mad = &evt->iu.channel_enquiry; @@ -5132,6 +5240,12 @@ static void ibmvfc_npiv_login(struct ibmvfc_host *vhost) struct ibmvfc_npiv_login_mad *mad; struct ibmvfc_event *evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + ibmvfc_dbg(vhost, "NPIV Login failed: no available events\n"); + ibmvfc_hard_reset_host(vhost); + return; + } + ibmvfc_gather_partition_info(vhost); ibmvfc_set_login_info(vhost); ibmvfc_init_event(evt, ibmvfc_npiv_login_done, IBMVFC_MAD_FORMAT); @@ -5196,6 +5310,12 @@ static void ibmvfc_npiv_logout(struct ibmvfc_host *vhost) struct ibmvfc_event *evt; evt = ibmvfc_get_event(&vhost->crq); + if (!evt) { + ibmvfc_dbg(vhost, "NPIV Logout failed: no available events\n"); + ibmvfc_hard_reset_host(vhost); + return; + } + ibmvfc_init_event(evt, ibmvfc_npiv_logout_done, IBMVFC_MAD_FORMAT); mad = &evt->iu.npiv_logout; -- 2.42.0
