scsi: lpfc: Validate hdwq pointers before dereferencing in reset/errata paths

When the HBA is undergoing a reset or is handling an errata event, NULL ptr
dereference crashes may occur in routines such as
lpfc_sli_flush_io_rings(), lpfc_dev_loss_tmo_callbk(), or
lpfc_abort_handler().

Add NULL ptr checks before dereferencing hdwq pointers that may have been
freed due to operations colliding with a reset or errata event handler.

Signed-off-by: Justin Tee <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin K. Petersen <[email protected]>

Author: Justin Tee

drivers/scsi/lpfc/lpfc_hbadisc.c

@@ -175,7 +175,8 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport)
 			 ndlp->nlp_state, ndlp->fc4_xpt_flags);
 
 	/* Don't schedule a worker thread event if the vport is going down. */
-	if (test_bit(FC_UNLOADING, &vport->load_flag)) {
+	if (test_bit(FC_UNLOADING, &vport->load_flag) ||
+	    !test_bit(HBA_SETUP, &phba->hba_flag)) {
 		spin_lock_irqsave(&ndlp->lock, iflags);
 		ndlp->rport = NULL;
 

drivers/scsi/lpfc/lpfc_scsi.c

@@ -5555,11 +5555,20 @@ lpfc_abort_handler(struct scsi_cmnd *cmnd)
 
 	iocb = &lpfc_cmd->cur_iocbq;
 	if (phba->sli_rev == LPFC_SLI_REV4) {
-		pring_s4 = phba->sli4_hba.hdwq[iocb->hba_wqidx].io_wq->pring;
-		if (!pring_s4) {
+		/* if the io_wq & pring are gone, the port was reset. */
+		if (!phba->sli4_hba.hdwq[iocb->hba_wqidx].io_wq ||
+		    !phba->sli4_hba.hdwq[iocb->hba_wqidx].io_wq->pring) {
+			lpfc_printf_vlog(vport, KERN_WARNING, LOG_FCP,
+					 "2877 SCSI Layer I/O Abort Request "
+					 "IO CMPL Status x%x ID %d LUN %llu "
+					 "HBA_SETUP %d\n", FAILED,
+					 cmnd->device->id,
+					 (u64)cmnd->device->lun,
+					 test_bit(HBA_SETUP, &phba->hba_flag));
 			ret = FAILED;
 			goto out_unlock_hba;
 		}
+		pring_s4 = phba->sli4_hba.hdwq[iocb->hba_wqidx].io_wq->pring;
 		spin_lock(&pring_s4->ring_lock);
 	}
 	/* the command is in process of being cancelled */

drivers/scsi/lpfc/lpfc_sli.c

@@ -4687,6 +4687,17 @@ lpfc_sli_flush_io_rings(struct lpfc_hba *phba)
 	/* Look on all the FCP Rings for the iotag */
 	if (phba->sli_rev >= LPFC_SLI_REV4) {
 		for (i = 0; i < phba->cfg_hdw_queue; i++) {
+			if (!phba->sli4_hba.hdwq ||
+			    !phba->sli4_hba.hdwq[i].io_wq) {
+				lpfc_printf_log(phba, KERN_ERR, LOG_SLI,
+						"7777 hdwq's deleted %lx "
+						"%lx %x %x\n",
+						phba->pport->load_flag,
+						phba->hba_flag,
+						phba->link_state,
+						phba->sli.sli_flag);
+				return;
+			}
 			pring = phba->sli4_hba.hdwq[i].io_wq->pring;
 
 			spin_lock_irq(&pring->ring_lock);