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From:   Johannes Thumshirn <jthumshirn@suse.de>
To:     "Martin K . Petersen" <martin.petersen@oracle.com>
Cc:     Linux Kernel Mailinglist <linux-kernel@vger.kernel.org>,
        Linux SCSI Mailinglist <linux-scsi@vger.kernel.org>,
        Johannes Thumshirn <jthumshirn@suse.de>,
        Hannes Reinecke <hare@suse.de>,
        Bart Van Asche <bvanasche@acm.org>,
        Christoph Hellwig <hch@lst.de>
Subject: [PATCH] scsi: sd: don't crash the host on invalid commands
Date:   Thu, 20 Sep 2018 09:15:50 +0200
Message-Id: <20180920071550.9866-1-jthumshirn@suse.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

When sd_init_command() get's a 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 Asche <bvanasche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>
---
 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 b79b366a94f7..19f28962d65b 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1276,7 +1276,8 @@ 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(1);
+		return BLKPREP_KILL;
 	}
 }
 
-- 
2.16.4