scsi: lpfc: Use list_for_each_entry_safe() in rscn_recovery_check()

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>

diff --git a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
index 583a287b2d0c2ef187366f4210e338123f5a4a34..3671e0f8e041acf22c6de5a810c72e9c17ad88b8 100644 (file)
--- a/drivers/scsi/lpfc/lpfc_els.c
+++ b/drivers/scsi/lpfc/lpfc_els.c
@@ -7708,10 +7708,10 @@ return_did_out:
 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;