Messages in this thread Patch in this message | | | Subject | Re: USB storage SCSI EH oops | From | "Martin K. Petersen" <> | Date | Sat, 14 Apr 2012 23:01:28 -0400 |
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>>>>> "Linus" == Linus Torvalds <torvalds@linux-foundation.org> writes:
Linus,
Linus> So I got the appended NULL pointer dereference with current -git Linus> (plus the RCU patches I'm testing, but they seem unrelated)..
I sent out the following patch earlier in the week but James hasn't picked it up yet...
SCSI: Fix error handling when no ULD is attached
Commit 18a4d0a2 introduced a bug in which we would attempt to dereference the scsi driver even when the device had no ULD attached.
Ensure that a driver is registered and make the driver accessor function more resilient to errors during device discovery.
Reported-by: Elric Fu <elricfu1@gmail.com> Reported-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c index 2cfcbff..386f0c5 100644 --- a/drivers/scsi/scsi_error.c +++ b/drivers/scsi/scsi_error.c @@ -835,7 +835,7 @@ static int scsi_send_eh_cmnd(struct scsi_cmnd *scmd, unsigned char *cmnd, scsi_eh_restore_cmnd(scmd, &ses); - if (sdrv->eh_action) + if (sdrv && sdrv->eh_action) rtn = sdrv->eh_action(scmd, cmnd, cmnd_size, rtn); return rtn; diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h index 377df4a..1e11985 100644 --- a/include/scsi/scsi_cmnd.h +++ b/include/scsi/scsi_cmnd.h @@ -134,6 +134,9 @@ struct scsi_cmnd { static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd) { + if (!cmd->request->rq_disk) + return NULL; + return *(struct scsi_driver **)cmd->request->rq_disk->private_data; }
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