[PATCH AUTOSEL 4.18 43/58] scsi: sd: don't crash the host on invalid commands

From: Sasha Levin
Date: Mon Oct 08 2018 - 11:26:11 EST

From: Johannes Thumshirn <jthumshirn@xxxxxxx>

[ 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@xxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxx>
Cc: Bart Van Assche <bvanassche@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
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)
return sd_zbc_setup_reset_cmnd(cmd);
- BUG();
+ return BLKPREP_KILL;