From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Sreekanth Reddy <sreekanth.reddy@broadcom.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 55/92] scsi: mpt3sas: Fix kernel panic during drive powercycle test
Date:   Mon, 29 Nov 2021 19:18:24 +0100
Message-Id: <20211129181709.256205607@linuxfoundation.org>
In-Reply-To: <20211129181707.392764191@linuxfoundation.org>
References: <20211129181707.392764191@linuxfoundation.org>
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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 3654cfc4376fa..97c1f242ef0a3 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_scsih.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_scsih.c
@@ -3387,7 +3387,7 @@ _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