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From:   Daniel Wagner <dwagner@suse.de>
To:     linux-scsi@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org,
        Dick Kennedy <dick.kennedy@broadcom.com>,
        Daniel Wagner <dwagner@suse.de>,
        James Smart <jsmart2021@gmail.com>
Subject: [PATCH] scsi: lpfc: Check queue pointer before use
Date:   Fri, 18 Oct 2019 18:21:11 +0200
Message-Id: <20191018162111.8798-1-dwagner@suse.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The queue pointer might not be valid. The rest of the code checks the
pointer before accessing it. lpfc_sli4_process_missed_mbox_completions
is the only place where the check is missing.

Fixes: 657add4e5e15 ("scsi: lpfc: Fix poor use of hardware queues if fewer irq vectors")
Cc: James Smart <jsmart2021@gmail.com>
Signed-off-by: Daniel Wagner <dwagner@suse.de>
---
Hi,

Not entirely sure if this correct. I tried to understand the logic of
the mentioned patch but failed to grasps all the details. Anyway, we
observe a crash in lpfc_sli4_process_missed_mbox_completions() while
iterating the array. All but the last one entry has a valid pointer.

Thanks,
Daniel

 drivers/scsi/lpfc/lpfc_sli.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 379c37451645..149966ba8a17 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -7906,7 +7906,7 @@ lpfc_sli4_process_missed_mbox_completions(struct lpfc_hba *phba)
 	if (sli4_hba->hdwq) {
 		for (eqidx = 0; eqidx < phba->cfg_irq_chann; eqidx++) {
 			eq = phba->sli4_hba.hba_eq_hdl[eqidx].eq;
-			if (eq->queue_id == sli4_hba->mbx_cq->assoc_qid) {
+			if (eq && eq->queue_id == sli4_hba->mbx_cq->assoc_qid) {
 				fpeq = eq;
 				break;
 			}
-- 
2.16.4