scsi: lpfc: Fix NULL pointer access in lpfc_nvme_info_show

After making remoteport unregister requests, the ndlp nrport pointer was
stale.

Track when waiting for waiting for unregister completion callback and
adjust nldp pointer assignment.  Add a few safety checks for NULL
pointer values.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_attr.c

@@ -149,6 +149,7 @@ lpfc_nvme_info_show(struct device *dev, struct device_attribute *attr,
 	struct lpfc_nvmet_tgtport *tgtp;
 	struct nvme_fc_local_port *localport;
 	struct lpfc_nvme_lport *lport;
+	struct lpfc_nvme_rport *rport;
 	struct lpfc_nodelist *ndlp;
 	struct nvme_fc_remote_port *nrport;
 	struct lpfc_nvme_ctrl_stat *cstat;
@@ -312,11 +313,14 @@ lpfc_nvme_info_show(struct device *dev, struct device_attribute *attr,
 			localport->port_id, statep);
 
 	list_for_each_entry(ndlp, &vport->fc_nodes, nlp_listp) {
-		if (!ndlp->nrport)
+		rport = lpfc_ndlp_get_nrport(ndlp);
+		if (!rport)
 			continue;
 
 		/* local short-hand pointer. */
-		nrport = ndlp->nrport->remoteport;
+		nrport = rport->remoteport;
+		if (!nrport)
+			continue;
 
 		/* Port state is only one of two values for now. */
 		switch (nrport->port_state) {
@@ -3290,6 +3294,9 @@ lpfc_update_rport_devloss_tmo(struct lpfc_vport *vport)
 {
 	struct Scsi_Host  *shost;
 	struct lpfc_nodelist  *ndlp;
+#if (IS_ENABLED(CONFIG_NVME_FC))
+	struct lpfc_nvme_rport *rport;
+#endif
 
 	shost = lpfc_shost_from_vport(vport);
 	spin_lock_irq(shost->host_lock);
@@ -3299,8 +3306,9 @@ lpfc_update_rport_devloss_tmo(struct lpfc_vport *vport)
 		if (ndlp->rport)
 			ndlp->rport->dev_loss_tmo = vport->cfg_devloss_tmo;
 #if (IS_ENABLED(CONFIG_NVME_FC))
-		if (ndlp->nrport)
-			nvme_fc_set_remoteport_devloss(ndlp->nrport->remoteport,
+		rport = lpfc_ndlp_get_nrport(ndlp);
+		if (rport)
+			nvme_fc_set_remoteport_devloss(rport->remoteport,
 						       vport->cfg_devloss_tmo);
 #endif
 	}

drivers/scsi/lpfc/lpfc_debugfs.c

@@ -552,6 +552,7 @@ lpfc_debugfs_nodelist_data(struct lpfc_vport *vport, char *buf, int size)
 	struct nvme_fc_local_port *localport;
 	struct lpfc_nvmet_tgtport *tgtp;
 	struct nvme_fc_remote_port *nrport;
+	struct lpfc_nvme_rport *rport;
 
 	cnt = (LPFC_NODELIST_SIZE / LPFC_NODELIST_ENTRY_SIZE);
 	outio = 0;
@@ -695,10 +696,13 @@ lpfc_debugfs_nodelist_data(struct lpfc_vport *vport, char *buf, int size)
 	len += snprintf(buf + len, size - len, "\tRport List:\n");
 	list_for_each_entry(ndlp, &vport->fc_nodes, nlp_listp) {
 		/* local short-hand pointer. */
-		if (!ndlp->nrport)
+		rport = lpfc_ndlp_get_nrport(ndlp);
+		if (!rport)
 			continue;
 
-		nrport = ndlp->nrport->remoteport;
+		nrport = rport->remoteport;
+		if (!nrport)
+			continue;
 
 		/* Port state is only one of two values for now. */
 		switch (nrport->port_state) {

drivers/scsi/lpfc/lpfc_nvme.c

@@ -335,6 +335,7 @@ lpfc_nvme_remoteport_delete(struct nvme_fc_remote_port *remoteport)
 			remoteport);
 	spin_lock_irq(&vport->phba->hbalock);
 	ndlp->nrport = NULL;
+	ndlp->upcall_flags &= ~NLP_WAIT_FOR_UNREG;
 	spin_unlock_irq(&vport->phba->hbalock);
 
 	/* Remove original register reference. The host transport
@@ -2646,6 +2647,7 @@ lpfc_nvme_register_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 	struct nvme_fc_local_port *localport;
 	struct lpfc_nvme_lport *lport;
 	struct lpfc_nvme_rport *rport;
+	struct lpfc_nvme_rport *oldrport;
 	struct nvme_fc_remote_port *remote_port;
 	struct nvme_fc_port_info rpinfo;
 	struct lpfc_nodelist *prev_ndlp;
@@ -2678,7 +2680,9 @@ lpfc_nvme_register_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 
 	rpinfo.port_name = wwn_to_u64(ndlp->nlp_portname.u.wwn);
 	rpinfo.node_name = wwn_to_u64(ndlp->nlp_nodename.u.wwn);
-	if (!ndlp->nrport)
+
+	oldrport = lpfc_ndlp_get_nrport(ndlp);
+	if (!oldrport)
 		lpfc_nlp_get(ndlp);
 
 	ret = nvme_fc_register_remoteport(localport, &rpinfo, &remote_port);
@@ -2688,8 +2692,8 @@ lpfc_nvme_register_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 		 * new rport.
 		 */
 		rport = remote_port->private;
-		if (ndlp->nrport) {
-			if (ndlp->nrport == remote_port->private) {
+		if (oldrport) {
+			if (oldrport == remote_port->private) {
 				/* Same remoteport.  Just reuse. */
 				lpfc_printf_vlog(ndlp->vport, KERN_INFO,
 						 LOG_NVME_DISC,
@@ -2713,6 +2717,7 @@ lpfc_nvme_register_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 			 */
 			spin_lock_irq(&vport->phba->hbalock);
 			ndlp->nrport = NULL;
+			ndlp->upcall_flags &= ~NLP_WAIT_FOR_UNREG;
 			spin_unlock_irq(&vport->phba->hbalock);
 			rport->ndlp = NULL;
 			rport->remoteport = NULL;
@@ -2785,7 +2790,7 @@ lpfc_nvme_unregister_port(struct lpfc_vport *vport, struct lpfc_nodelist *ndlp)
 	if (!lport)
 		goto input_err;
 
-	rport = ndlp->nrport;
+	rport = lpfc_ndlp_get_nrport(ndlp);
 	if (!rport)
 		goto input_err;
 

drivers/scsi/lpfc/lpfc_nvme.h

@@ -30,6 +30,10 @@
 #define LPFC_NVME_FB_SHIFT		9
 #define LPFC_NVME_MAX_FB		(1 << 20)	/* 1M */
 
+#define lpfc_ndlp_get_nrport(ndlp)					\
+	((!ndlp->nrport || (ndlp->upcall_flags & NLP_WAIT_FOR_UNREG))	\
+	? NULL : ndlp->nrport)
+
 struct lpfc_nvme_qhandle {
 	uint32_t index;		/* WQ index to use */
 	uint32_t qidx;		/* queue index passed to create */