Bug#257542: Kernel panics when cdrom mounted

[David Lawyer <dave@lafn.org>]

Package: kernel-image-2.6.6-1-386
Version: -1

When I try to mount my old cdrom, it hesitates for a while and then
Linux crashes with the following message on the bottom of the screen:
Kernel panic: Fatal exception in interrupt In interrupt handler - not
syncing

This is repeatable.  But it doesn't happen in kernel-image-2.4-586tsc.
There are also a lot of other message lines above the panic message such
as cdrom_start ... but I didn't copy them down.  In fact, many of them had
scrolled off the screen.

Here's the data on my cdrom using hdparm -I :

/dev/hdc:

ATAPI CD-ROM, with removable media
	Model Number:       FX600S                                  
	Serial Number:      
	Firmware Revision:  P01     
Standards:
	Likely used CD-ROM ATAPI-1
Configuration:
	DRQ response: <=10ms with INTRQ
	Packet size: 12 bytes
Capabilities:
	LBA, IORDY(can be disabled)
	Buffer size: 256.0kB
	DMA: *sdma0 *sdma1 *sdma2 *mdma0 *mdma1 (?)
	     Cycle time: min=150ns recommended=230ns
	PIO: pio0 pio1 pio2 pio3 
	     Cycle time: no flow control=230ns  IORDY flow control=180ns

------------------------------------------------------------------------
I think there are two problems here.  One is that I don't think the
kernel should crash due to cdrom driver problems.  The second is the
problem with the cdrom driver itself.

If I run "dcd" for playing a CD recording, it works OK even though there
are some error messages.  Here are boot-time messages for kernel 2.4:

Jul  2 15:05:20 davespc1 kernel: hdc: FX600S, ATAPI CD/DVD-ROM drive

Jul  2 15:05:20 davespc1 kernel: ide1 at 0x170-0x177,0x376 on irq 15

Jul  2 15:05:20 davespc1 kernel: hdc: attached ide-cdrom driver.
Jul  2 15:05:20 davespc1 kernel: hdc: ATAPI 6X CD-ROM drive, 256kB Cache, DMA
Jul  2 15:05:20 davespc1 kernel: Uniform CD-ROM driver Revision: 3.12
Jul  2 15:05:20 davespc1 kernel: hdc: DMA interrupt recovery
Jul  2 15:05:20 davespc1 kernel: hdc: cdrom_decode_status: status=0xd0 { Busy }
Jul  2 15:05:20 davespc1 kernel: hdc: cdrom_decode_status: error=0xd0LastFailedSense 0x0d 
Jul  2 15:05:20 davespc1 kernel: hdc: DMA disabled
------------------------------------------------------------------------------
Note that DMA was disabled by the above, enabling the cdrom to work OK.
DMA here really means bus mastering DMA and not the obsolete mdma
(Multi-Word DMA) or sdma (Single-Word DMA) supported by the physical
cdrom.  Also note the CD driver is 3.12 (3.20 is used for kernel 2.6).

Here's selected messages from dmesg, also for 2.4.  It shows about the
same as above.

Linux version 2.4.26-1-586tsc (herbert@gondolin) (gcc version 3.3.3 (Debian 20040401)) #1 Sat May 1 16:46:38 EST 2004
Uniform Multi-Platform E-IDE driver Revision: 7.00beta4-2.4
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
ide: late registration of driver.
PIIX4: IDE controller at PCI slot 00:07.1
PIIX4: chipset revision 1
PIIX4: not 100% native mode: will probe irqs later
    ide1: BM-DMA at 0xf008-0xf00f, BIOS settings: hdc:pio, hdd:pio
hdc: FX600S, ATAPI CD/DVD-ROM drive
ide1 at 0x170-0x177,0x376 on irq 15
hdc: attached ide-cdrom driver.
hdc: ATAPI 6X CD-ROM drive, 256kB Cache, DMA
Uniform CD-ROM driver Revision: 3.12
hdc: drive_cmd: status=0x51 { DriveReady SeekComplete Error }
hdc: drive_cmd: error=0x04Aborted Command 
hdc: drive_cmd: status=0x51 { DriveReady SeekComplete Error }
hdc: drive_cmd: error=0x04Aborted Command 
hdc: drive_cmd: status=0x51 { DriveReady SeekComplete Error }
hdc: drive_cmd: error=0x04Aborted Command 
hdc: DMA interrupt recovery
hdc: lost interrupt
hdc: cdrom_decode_status: status=0xd0 { Busy }
hdc: cdrom_decode_status: error=0xd0LastFailedSense 0x0d 
hdc: DMA disabled
hdc: ATAPI reset complete
hdc: drive_cmd: status=0x51 { DriveReady SeekComplete Error }
hdc: drive_cmd: error=0x04Aborted Command 
------------------------------------------------------------------------
Here's a couple of messages for 2.6, but I think it happened when I
tried to mount the cdrom as I didn't find it in dmesg:

Jul  2 14:33:49 davespc1 kernel: hdc: ATAPI 6X CD-ROM drive, 256kB Cache, DMA
Jul  2 14:33:49 davespc1 kernel: Uniform CD-ROM driver Revision: 3.20

Note that the driver is 3.20 while the driver I use in kernel 2.4 is
3.12.  Perhaps this difference account for the different behavior.  Is
there a way to capture the kernel messages just prior to the kernel
panic message?

			David Lawyer