[PATCH 4.4 16/52] scsi: mpt3sas: Fix kernel panic during drive powercycle test

Greg Kroah-Hartman
2021-12-06T15:01:49Z

From: Sreekanth Reddy <sreekanth.reddy@broadcom.com>

[ Upstream commit 0ee4ba13e09c9d9c1cb6abb59da8295d9952328b ]

While looping over shost's sdev list it is possible that one
of the drives is getting removed and its sas_target object is
freed but its sdev object remains intact.

Consequently, a kernel panic can occur while the driver is trying to access
the sas_address field of sas_target object without also checking the
sas_target object for NULL.

Link: https://lore.kernel.org/r/20211117104909.2069-1-sreekanth.reddy@broadcom.com
Fixes: f92363d12359 ("[SCSI] mpt3sas: add new driver supporting 12GB SAS")
Signed-off-by: Sreekanth Reddy <sreekanth.reddy@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 | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_scsih.c b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
index 49b751a8f5f3b..0e39bb1489ac7 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -2904,7 +2904,7 @@ _scsih_ublock_io_device(struct MPT3SAS_ADAPTER *ioc, u64 sas_address)

shost_for_each_device(sdev, ioc->shost) {
sas_device_priv_data = sdev->hostdata;
- if (!sas_device_priv_data)
+ if (!sas_device_priv_data || !sas_device_priv_data->sas_target)
continue;
if (sas_device_priv_data->sas_target->sas_address
!= sas_address)
--
2.33.0