lpfc: fix race between LOGO/PLOGI handling causing NULL pointer

Fix race between LOGO/PLOGI handling causing NULL pointer
Signed-off-by: James Smart <james.smart@emulex.com>
Signed-off-by: Dick Kennedy <dick.kennedy@emulex.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/lpfc/lpfc_disc.h

@@ -78,7 +78,8 @@ struct lpfc_nodelist {
 	struct list_head nlp_listp;
 	struct lpfc_name nlp_portname;
 	struct lpfc_name nlp_nodename;
-	uint32_t         nlp_flag;		/* entry  flags */
+	uint32_t         nlp_flag;		/* entry flags */
+	uint32_t         nlp_add_flag;		/* additional flags */
 	uint32_t         nlp_DID;		/* FC D_ID of entry */
 	uint32_t         nlp_last_elscmd;	/* Last ELS cmd sent */
 	uint16_t         nlp_type;
@@ -157,6 +158,9 @@ struct lpfc_node_rrq {
 #define NLP_FIRSTBURST     0x40000000	/* Target supports FirstBurst */
 #define NLP_RPI_REGISTERED 0x80000000	/* nlp_rpi is valid */
 
+/* Defines for nlp_add_flag (uint32) */
+#define NLP_IN_DEV_LOSS  0x00000001	/* Dev Loss processing in progress */
+
 /* ndlp usage management macros */
 #define NLP_CHK_NODE_ACT(ndlp)		(((ndlp)->nlp_usg_map \
 						& NLP_USG_NODE_ACT_BIT) \

drivers/scsi/lpfc/lpfc_els.c

@@ -6693,6 +6693,13 @@ lpfc_els_unsol_buffer(struct lpfc_hba *phba, struct lpfc_sli_ring *pring,
 
 	phba->fc_stat.elsRcvFrame++;
 
+	/*
+	 * Do not process any unsolicited ELS commands
+	 * if the ndlp is in DEV_LOSS
+	 */
+	if (ndlp->nlp_add_flag & NLP_IN_DEV_LOSS)
+		goto dropit;
+
 	elsiocb->context1 = lpfc_nlp_get(ndlp);
 	elsiocb->vport = vport;
 

drivers/scsi/lpfc/lpfc_hbadisc.c

@@ -153,6 +153,16 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport)
 			put_device(&rport->dev);
 			return;
 		}
+
+		put_node = rdata->pnode != NULL;
+		put_rport = ndlp->rport != NULL;
+		rdata->pnode = NULL;
+		ndlp->rport = NULL;
+		if (put_node)
+			lpfc_nlp_put(ndlp);
+		if (put_rport)
+			put_device(&rport->dev);
+		return;
 	}
 
 	evtp = &ndlp->dev_loss_evt;
@@ -161,6 +171,7 @@ lpfc_dev_loss_tmo_callbk(struct fc_rport *rport)
 		return;
 
 	evtp->evt_arg1  = lpfc_nlp_get(ndlp);
+	ndlp->nlp_add_flag |= NLP_IN_DEV_LOSS;
 
 	spin_lock_irq(&phba->hbalock);
 	/* We need to hold the node by incrementing the reference
@@ -201,8 +212,10 @@ lpfc_dev_loss_tmo_handler(struct lpfc_nodelist *ndlp)
 
 	rport = ndlp->rport;
 
-	if (!rport)
+	if (!rport) {
+		ndlp->nlp_add_flag &= ~NLP_IN_DEV_LOSS;
 		return fcf_inuse;
+	}
 
 	rdata = rport->dd_data;
 	name = (uint8_t *) &ndlp->nlp_portname;
@@ -235,6 +248,7 @@ lpfc_dev_loss_tmo_handler(struct lpfc_nodelist *ndlp)
 		put_rport = ndlp->rport != NULL;
 		rdata->pnode = NULL;
 		ndlp->rport = NULL;
+		ndlp->nlp_add_flag &= ~NLP_IN_DEV_LOSS;
 		if (put_node)
 			lpfc_nlp_put(ndlp);
 		if (put_rport)
@@ -250,6 +264,7 @@ lpfc_dev_loss_tmo_handler(struct lpfc_nodelist *ndlp)
 				 *name, *(name+1), *(name+2), *(name+3),
 				 *(name+4), *(name+5), *(name+6), *(name+7),
 				 ndlp->nlp_DID);
+		ndlp->nlp_add_flag &= ~NLP_IN_DEV_LOSS;
 		return fcf_inuse;
 	}
 
@@ -259,6 +274,7 @@ lpfc_dev_loss_tmo_handler(struct lpfc_nodelist *ndlp)
 		put_rport = ndlp->rport != NULL;
 		rdata->pnode = NULL;
 		ndlp->rport = NULL;
+		ndlp->nlp_add_flag &= ~NLP_IN_DEV_LOSS;
 		if (put_node)
 			lpfc_nlp_put(ndlp);
 		if (put_rport)
@@ -297,6 +313,7 @@ lpfc_dev_loss_tmo_handler(struct lpfc_nodelist *ndlp)
 	put_rport = ndlp->rport != NULL;
 	rdata->pnode = NULL;
 	ndlp->rport = NULL;
+	ndlp->nlp_add_flag &= ~NLP_IN_DEV_LOSS;
 	if (put_node)
 		lpfc_nlp_put(ndlp);
 	if (put_rport)