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From:   Sasha Levin <sashal@kernel.org>
To:     stable@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     Johannes Thumshirn <jthumshirn@suse.de>,
        Hannes Reinecke <hare@suse.de>,
        Bart Van Assche <bvanassche@acm.org>,
        Christoph Hellwig <hch@lst.de>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH AUTOSEL 4.18 43/58] scsi: sd: don't crash the host on invalid commands
Date:   Mon,  8 Oct 2018 11:25:08 -0400
Message-Id: <20181008152523.70705-43-sashal@kernel.org>
In-Reply-To: <20181008152523.70705-1-sashal@kernel.org>
References: <20181008152523.70705-1-sashal@kernel.org>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Johannes Thumshirn <jthumshirn@suse.de>

[ Upstream commit f1f1fadacaf08b7cf11714c0c29f8fa4d4ef68a9 ]

When sd_init_command() get's a command with a unknown req_op() it crashes the
system via BUG().

This makes debugging the actual reason for the broken request cmd_flags pretty
hard as the system is down before it's able to write out debugging data on the
serial console or the trace buffer.

Change the BUG() to a WARN_ON() and return BLKPREP_KILL to fail gracefully and
return an I/O error to the producer of the request.

Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 drivers/scsi/sd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 9421d9877730..0949d3db56e7 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1277,7 +1277,8 @@ static int sd_init_command(struct scsi_cmnd *cmd)
 	case REQ_OP_ZONE_RESET:
 		return sd_zbc_setup_reset_cmnd(cmd);
 	default:
-		BUG();
+		WARN_ON_ONCE(1);
+		return BLKPREP_KILL;
 	}
 }
 
-- 
2.17.1