[PATCH 5.6 006/167] scsi: lpfc: Fix crash after handling a pci error

[Greg Kroah-Hartman]

From: James Smart <jsmart2021@xxxxxxxxx>

[ Upstream commit 4cd70891308dfb875ef31060c4a4aa8872630a2e ]

Injecting EEH on a 32GB card is causing kernel oops

The pci error handler is doing an IO flush and the offline code is also
doing an IO flush. When the 1st flush is complete the hdwq is destroyed
(freed), yet the second flush accesses the hdwq and crashes.

Added a check in lpfc_sli4_fush_io_rings to check both the HBA_IOQ_FLUSH
flag and the hdwq pointer to see if it is already set and not already
freed.

Link: https://lore.kernel.org/r/20200322181304.37655-6-jsmart2021@xxxxxxxxx
Signed-off-by: James Smart <jsmart2021@xxxxxxxxx>
Signed-off-by: Dick Kennedy <dick.kennedy@xxxxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/scsi/lpfc/lpfc_sli.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index 5939ea0e3b1eb..de97727458fc7 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -4046,6 +4046,11 @@ lpfc_sli_flush_io_rings(struct lpfc_hba *phba)
 	struct lpfc_iocbq *piocb, *next_iocb;
 
 	spin_lock_irq(&phba->hbalock);
+	if (phba->hba_flag & HBA_IOQ_FLUSH ||
+	    !phba->sli4_hba.hdwq) {
+		spin_unlock_irq(&phba->hbalock);
+		return;
+	}
 	/* Indicate the I/O queues are flushed */
 	phba->hba_flag |= HBA_IOQ_FLUSH;
 	spin_unlock_irq(&phba->hbalock);
-- 
2.20.1