Re: CDROM troubles -- some progress, problem remains

[Phil Stracchino]

On Mon, May 07, 2001 at 12:01:16AM +0200, Jens Axboe wrote:
> On Sun, May 06 2001, Phil Stracchino wrote:
> > On Sun, May 06, 2001 at 03:05:00AM -0700, Phil Stracchino wrote:
> > > Hey folks,
> > > I'm seeing a problem with mounting CDs using a Toshiba XM-6401TA CDROM
> > > drive attached to an Adaptec AHA1542CF controller (scsi1) on kernel 2.4.3
> > > and 2.4.4.  The behavior seems to be fairly consistent as follows:
> > > 
> > > first mount and unmount works normally, no unusual events logged
> > > second mount and unmount works normally, no unusual events logged
> > > third mount locks up the machine.  looks like a kernel panic.
> > > 
> > > Any ideas?
> > 
> > 
> > Panic is confirmed.  This time, it lived long enough to log:
> >  
> > May  6 14:05:05 babylon5 kernel: Kernel panic: scsi_free:Bad offset
> > 
> > Since it involves the CDROM, the aha1542 driver is implicated.  Why it's
> > getting a bad offset, I don't understand enough about the SCSI drivers to
> > know; all the scsi_free calls in aha1542.c look identical to me.
> >  
> > Would any Linux SCSI gurus care to let me know any diagnostic procedures
> > recommended for nailing this one?
> 
> The panic should be fixed with attached patch.

The patch does indeed seem to prevent the panic, but not the underlying
problem.  Here's the results of a series of mount/umount operations after
applying the patch:

	*** CD inserted
VFS: Disk change detected on device sr(11,0)
	*** first mount (succeeded)
ISO 9660 Extensions: RRIP_1991A
	*** second mount (succeeded)
ISO 9660 Extensions: RRIP_1991A
	*** third mount (succeeded)
ISO 9660 Extensions: RRIP_1991A
	*** fourth and subsequent mounts failed
sr: ran out of mem for scatter pad
 I/O error: dev 0b:00, sector 252
isofs_read_super: bread failed, dev=0b:00, iso_blknum=63, block=126
sr: ran out of mem for scatter pad
 I/O error: dev 0b:00, sector 0
sr: ran out of mem for scatter pad
 I/O error: dev 0b:00, sector 64
sr: ran out of mem for scatter pad
 I/O error: dev 0b:00, sector 0
	*** the last manual mount attempt
sr: ran out of mem for scatter pad
 I/O error: dev 0b:00, sector 64
	*** at this point I logged out, then logged back in as a different
	    user
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
sr: ran out of mem for scatter pad
 I/O error: dev 0b:00, sector 0
sr: ran out of mem for scatter pad
 I/O error: dev 0b:00, sector 64
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers
Warning - running *really* short on DMA buffers

The kernel is continuing to spew these warnings.  At the time of finishing
this message, there are now 51 of them.

-- 
 Linux Now!   ..........Because friends don't let friends use Microsoft.
 phil stracchino   --   the renaissance man   --   mystic zen biker geek
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