[PATCH 4.14 107/193] scsi: lpfc: fix pci hot plug crash in list_add call

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Dick Kennedy <dick.kennedy@xxxxxxxxxxxx>

commit 401bb4169da655f3e5d28d0b208182e1ab60bf2a upstream.

During pci hot plug, the kernel crashes in a list_add_call

The lookup by tag function will return null if the IOCB is out of range
or does not have the on txcmplq flag set.

Fix: Check for null return from lookup by tag.

Signed-off-by: Dick Kennedy <dick.kennedy@xxxxxxxxxxxx>
Signed-off-by: James Smart <james.smart@xxxxxxxxxxxx>
Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/scsi/lpfc/lpfc_sli.c |   17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -12507,19 +12507,21 @@ lpfc_sli4_els_wcqe_to_rspiocbq(struct lp
 	/* Look up the ELS command IOCB and create pseudo response IOCB */
 	cmdiocbq = lpfc_sli_iocbq_lookup_by_tag(phba, pring,
 				bf_get(lpfc_wcqe_c_request_tag, wcqe));
-	/* Put the iocb back on the txcmplq */
-	lpfc_sli_ringtxcmpl_put(phba, pring, cmdiocbq);
-	spin_unlock_irqrestore(&pring->ring_lock, iflags);
-
 	if (unlikely(!cmdiocbq)) {
+		spin_unlock_irqrestore(&pring->ring_lock, iflags);
 		lpfc_printf_log(phba, KERN_WARNING, LOG_SLI,
 				"0386 ELS complete with no corresponding "
-				"cmdiocb: iotag (%d)\n",
-				bf_get(lpfc_wcqe_c_request_tag, wcqe));
+				"cmdiocb: 0x%x 0x%x 0x%x 0x%x\n",
+				wcqe->word0, wcqe->total_data_placed,
+				wcqe->parameter, wcqe->word3);
 		lpfc_sli_release_iocbq(phba, irspiocbq);
 		return NULL;
 	}
 
+	/* Put the iocb back on the txcmplq */
+	lpfc_sli_ringtxcmpl_put(phba, pring, cmdiocbq);
+	spin_unlock_irqrestore(&pring->ring_lock, iflags);
+
 	/* Fake the irspiocbq and copy necessary response information */
 	lpfc_sli4_iocb_param_transfer(phba, irspiocbq, cmdiocbq, wcqe);
 
@@ -17137,7 +17139,8 @@ exit:
 	if (pcmd && pcmd->virt)
 		dma_pool_free(phba->lpfc_drb_pool, pcmd->virt, pcmd->phys);
 	kfree(pcmd);
-	lpfc_sli_release_iocbq(phba, iocbq);
+	if (iocbq)
+		lpfc_sli_release_iocbq(phba, iocbq);
 	lpfc_in_buf_free(phba, &dmabuf->dbuf);
 }