[PATCH AUTOSEL 4.14 001/127] scsi: lpfc: Fix kernel Oops due to null pring pointers

[Sasha Levin]

From: James Smart <jsmart2021@xxxxxxxxx>

[ Upstream commit 5a9eeff57f340238c39c95d8e7e54c96fc722de7 ]

Driver is hitting null pring pointers in lpfc_do_work().

Pointer assignment occurs based on SLI-revision. If recovering after an
error, its possible the sli revision for the port was cleared, making the
lpfc_phba_elsring() not return a ring pointer, thus the null pointer.

Add SLI revision checking to lpfc_phba_elsring() and status checking to all
callers.

Signed-off-by: Dick Kennedy <dick.kennedy@xxxxxxxxxxxx>
Signed-off-by: James Smart <jsmart2021@xxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/scsi/lpfc/lpfc.h      | 6 ++++++
 drivers/scsi/lpfc/lpfc_els.c  | 2 ++
 drivers/scsi/lpfc/lpfc_init.c | 7 ++++++-
 drivers/scsi/lpfc/lpfc_sli.c  | 2 ++
 4 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/lpfc/lpfc.h b/drivers/scsi/lpfc/lpfc.h
index bc61cc8bc6f02..03e95a3216c8c 100644
--- a/drivers/scsi/lpfc/lpfc.h
+++ b/drivers/scsi/lpfc/lpfc.h
@@ -1239,6 +1239,12 @@ lpfc_sli_read_hs(struct lpfc_hba *phba)
 static inline struct lpfc_sli_ring *
 lpfc_phba_elsring(struct lpfc_hba *phba)
 {
+	/* Return NULL if sli_rev has become invalid due to bad fw */
+	if (phba->sli_rev != LPFC_SLI_REV4  &&
+	    phba->sli_rev != LPFC_SLI_REV3  &&
+	    phba->sli_rev != LPFC_SLI_REV2)
+		return NULL;
+
 	if (phba->sli_rev == LPFC_SLI_REV4) {
 		if (phba->sli4_hba.els_wq)
 			return phba->sli4_hba.els_wq->pring;
diff --git a/drivers/scsi/lpfc/lpfc_els.c b/drivers/scsi/lpfc/lpfc_els.c
index ddd29752d96dc..0032465d1b630 100644
--- a/drivers/scsi/lpfc/lpfc_els.c
+++ b/drivers/scsi/lpfc/lpfc_els.c
@@ -1335,6 +1335,8 @@ lpfc_els_abort_flogi(struct lpfc_hba *phba)
 			Fabric_DID);
 
 	pring = lpfc_phba_elsring(phba);
+	if (unlikely(!pring))
+		return -EIO;
 
 	/*
 	 * Check the txcmplq for an iocb that matches the nport the driver is
diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index 25612ccf6ff28..1da125afebddb 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -1773,7 +1773,12 @@ lpfc_sli4_port_sta_fn_reset(struct lpfc_hba *phba, int mbx_action,
 	lpfc_offline(phba);
 	/* release interrupt for possible resource change */
 	lpfc_sli4_disable_intr(phba);
-	lpfc_sli_brdrestart(phba);
+	rc = lpfc_sli_brdrestart(phba);
+	if (rc) {
+		lpfc_printf_log(phba, KERN_ERR, LOG_INIT,
+				"6309 Failed to restart board\n");
+		return rc;
+	}
 	/* request and enable interrupt */
 	intr_mode = lpfc_sli4_enable_intr(phba, phba->intr_mode);
 	if (intr_mode == LPFC_INTR_ERROR) {
diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 6c2b098b76095..0128ea32b208f 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -4421,6 +4421,8 @@ lpfc_sli_brdrestart_s4(struct lpfc_hba *phba)
 	hba_aer_enabled = phba->hba_flag & HBA_AER_ENABLED;
 
 	rc = lpfc_sli4_brdreset(phba);
+	if (rc)
+		return rc;
 
 	spin_lock_irq(&phba->hbalock);
 	phba->pport->stopped = 0;
-- 
2.20.1