From: James Smart <jsmart2021@gmail.com>
Date: Thu, 5 May 2022 20:55:13 -0700
Subject: scsi: lpfc: Use list_for_each_entry_safe() in rscn_recovery_check()
Patch-mainline: v5.19-rc1
Git-commit: 4a0f4aff3ce5a3efdf674f3bc1ba7d2642fa55ea
References: bsc#1200045

In GID_PT mode with lpfc_ns_query=1, a race condition between iterating the
vport->fc_nodes list in lpfc_rscn_recovery_check() and cleanup of an ndlp
can trigger a crash while processing the RSCN of another initiator from the
same zone.

During iteration of the vport->fc_nodes list, an ndlp is cleaned up and
released. lpfc_dequeue_node() is called from lpfc_cleanup_node() leading to
a bad ndlp dereference in lpfc_rscn_recovery_check().

Change list_for_each_entry() to list_for_each_entry_safe() in
lpfc_rscn_recovery_check() to protect against removal of an initiator ndlp,
while walking the vport->fc_nodes list.

Link: https://lore.kernel.org/r/20220506035519.50908-7-jsmart2021@gmail.com
Co-developed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/scsi/lpfc/lpfc_els.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/scsi/lpfc/lpfc_els.c
+++ b/drivers/scsi/lpfc/lpfc_els.c
@@ -7708,10 +7708,10 @@ lpfc_rscn_payload_check(struct lpfc_vpor
 static int
 lpfc_rscn_recovery_check(struct lpfc_vport *vport)
 {
-	struct lpfc_nodelist *ndlp = NULL;
+	struct lpfc_nodelist *ndlp = NULL, *n;
 
 	/* Move all affected nodes by pending RSCNs to NPR state. */
-	list_for_each_entry(ndlp, &vport->fc_nodes, nlp_listp) {
+	list_for_each_entry_safe(ndlp, n, &vport->fc_nodes, nlp_listp) {
 		if ((ndlp->nlp_state == NLP_STE_UNUSED_NODE) ||
 		    !lpfc_rscn_payload_check(vport, ndlp->nlp_DID))
 			continue;