scsi: sd: don't crash the host on invalid commands

[ 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index f8b6bf56c48e20c93b9322d87fe26653205c2793..ab999c4444b8cde0be3d86b30064332148d2931e 100644 (file)
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1158,7 +1158,8 @@ static int sd_init_command(struct scsi_cmnd *cmd)
        case REQ_OP_WRITE:
                return sd_setup_read_write_cmnd(cmd);
        default:
-               BUG();
+               WARN_ON_ONCE(1);
+               return BLKPREP_KILL;
        }
 }