[PATCH 5.12 063/292] scsi: mpt3sas: Fix deadlock while cancelling the running firmware event

Greg Kroah-Hartman
2021-07-19T18:00:00Z

From: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>

[ Upstream commit e2fac6c44ae06e58ac02181b048af31195883c31 ]

Do not cancel current running firmware event work if the event type is
different from MPT3SAS_REMOVE_UNRESPONDING_DEVICES. Otherwise a deadlock
can be observed while cancelling the current firmware event work if a hard
reset operation is called as part of processing the current event.

Link: https://lore.kernel.org/r/20210518051625.1596742-2-suganath-prabu.subramani@broadcom.com
Signed-off-by: Suganath Prabu S <suganath-prabu.subramani@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/scsi/mpt3sas/mpt3sas_scsih.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index 7824e77bc6e2..15d1f1fbeee7 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -3696,6 +3696,28 @@ _scsih_fw_event_cleanup_queue(struct MPT3SAS_ADAPTER *ioc)
ioc->fw_events_cleanup = 1;
while ((fw_event = dequeue_next_fw_event(ioc)) ||
(fw_event = ioc->current_event)) {
+
+ /*
+ * Don't call cancel_work_sync() for current_event
+ * other than MPT3SAS_REMOVE_UNRESPONDING_DEVICES;
+ * otherwise we may observe deadlock if current
+ * hard reset issued as part of processing the current_event.
+ *
+ * Orginal logic of cleaning the current_event is added
+ * for handling the back to back host reset issued by the user.
+ * i.e. during back to back host reset, driver use to process
+ * the two instances of MPT3SAS_REMOVE_UNRESPONDING_DEVICES
+ * event back to back and this made the drives to unregister
+ * the devices from SML.
+ */
+
+ if (fw_event == ioc->current_event &&
+ ioc->current_event->event !=
+ MPT3SAS_REMOVE_UNRESPONDING_DEVICES) {
+ ioc->current_event = NULL;
+ continue;
+ }
+
/*
* Wait on the fw_event to complete. If this returns 1, then
* the event was never executed, and we need a put for the
--
2.30.2