On Wed, Aug 19, 1998 at 01:52:03AM +0100, Richard Waltham wrote:
> Hi,
>
> I can generate the following panic in scsi.c at will using a CD media
> changer - Nakamichi MBR-7.
>
> Happens with kernel versions 2.0.35 and 2.0.36-pre6. I haven't checked any
> others.
>
> Attempt to allocate device channel 0, target 6, lun x
> Kernel Panic: No Device found in allocate_device().
>
> If I start the following two commands running in different vc's
>
> dd if=/dev/scdX of=/dev/null (X = 1, 2 ...)
>
> dd if=/dev/scdY of=/dev/null (Y = 0, 1 ...)
>
> and the second one started has Y < X I get the panic.
>
> eg
>
> dd if=/dev/sdc1 of=/dev/null - starting this first
>
> dd if=/dev/scd0 of=/dev/null - then starting this
>
> generates the panic. Starting scd0 first and then scd1 is OK - but very
> sloooooow as its spending most of the time changing CDs;)
>
> I guess the panic is caused by the call to allocate_device from
> do_sr_request in sr.c but don't know why.
>
> Anyone figure it out?
There have been reports that the code in scsi.c doesn't correctly honour the
BLIST_SINGLELUN and that this causes problems with Nakamichi MBR-7(2) and
certain host adapter settings. (Probably other devices will be affected too.)
Adding the NAKAMICHI to the blacklist (BLIST_SINGLELUN) and applying the
appended patch may help you. Chiaki Ishikawa reported successful operation
after creating the patch.
If I correctly judge what I see, this was a bug in scsi.c. Alan, is this bug
still in 2.0.36? (I'm not sure if it's the correct fix, though. There have
been reports about missing locking in sr.c, too ...)
-- Kurt Garloff, Dortmund <K.Garloff@ping.de> PGP key on http://student.physik.uni-dortmund.de/homepages/garloff--4Ckj6UjgE2iN1+kY Content-Type: text/plain; charset=us-ascii Content-Description: scsi-c-patch Content-Disposition: attachment; filename=scsi-c-patch
*** 1.3 1998/08/06 13:31:25 --- linux/drivers/scsi/scsi.c 1998/08/09 19:27:19 *************** *** 64,70 **** #undef USE_STATIC_SCSI_MEMORY /* ! static const char RCSid[] = "$Header: /usr/src/linux-2.0.xx/drivers/scsi/RCS/scsi.c,v 1.3 1998/08/06 13:31:25 guest Exp $"; */ --- 64,70 ---- #undef USE_STATIC_SCSI_MEMORY /* ! static const char RCSid[] = "$Header: /usr/src/linux-2.0.xx/drivers/scsi/RCS/scsi.c,v 1.4 1998/08/07 08:20:32 guest Exp guest $"; */ *************** *** 766,771 **** --- 766,780 ---- if ((bflags & BLIST_BORKEN) == 0) SDpnt->borken = 0; + /* ---moved as well --- */ + /* + * If we want to only allow I/O to one of the luns attached to this device + * at a time, then we set this flag. + */ + if (bflags & BLIST_SINGLELUN) + SDpnt->single_lun = 1; + + /* * These devices need this "key" to unlock the devices so we can use it */ *************** *** 808,813 **** --- 817,823 ---- if (bflags & BLIST_NOLUN) return 0; /* break; */ + /* we duplicated the following above after borken */ /* * If we want to only allow I/O to one of the luns attached to this device * at a time, then we set this flag. *************** *** 961,966 **** --- 971,985 ---- SCpnt = SCpnt->device_next; } } else { + /* + ** + printk("single_lun: LINE=%d, (%d,%d,%d)\n", + __LINE__, + device->channel, + device->id, + device->lun); + ** + */ SCpnt = device->host->host_queue; while(SCpnt){ if(SCpnt->channel == device->channel *************** *** 1092,1097 **** --- 1111,1126 ---- SCpnt = SCpnt->device_next; } } else { + /* + ** + printk("single_lun: LINE=%d, (%d,%d,%d)\n", + __LINE__, + device->channel, + device->id, + device->lun); + ** + */ + SCpnt = device->host->host_queue; while(SCpnt){ if(SCpnt->channel == device->channel
--4Ckj6UjgE2iN1+kY--
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