Re: new kernel oops in recent kernels

[Matthew Wilcox <matthew@wil.cx>]

On Sun, Mar 16, 2008 at 07:29:07PM +0100, Giuseppe Sacco wrote:
> > > [<ffffffff802460b0>] sr_drive_status+0x50/0xe8
> > > [<ffffffff8024bb84>] cdrom_ioctl+0x5f4/0x1208
> > > [<ffffffff80245c6c>] sr_block_ioctl+0x64/0xe8
> > 

> 0xffffffff802460a4 <sr_drive_status+68>:	daddiu	sp,sp,32
> 0xffffffff802460a8 <sr_drive_status+72>:	jal	0xffffffff8024c838 <cdrom_get_media_event>
> 0xffffffff802460ac <sr_drive_status+76>:	move	a1,sp
> 0xffffffff802460b0 <sr_drive_status+80>:	bnez	v0,0xffffffff802460fc <sr_drive_status+156>

I think I was confused earlier.  156 is 0x9c, thus within the function.
The backtrace must be incorrect; this is really 0x48 and thus a call to
cdrom_get_media_event, which points the finger at
cdi->ops->generic_packet being NULL.

Put a BUG_ON(!cdi->ops->generic_packet) in drivers/cdrom/cdrom.c right
before the line that calls it (ie line 11 of cdrom_get_media_event).
That should trigger and give a better backtrace.  Then it's a simple (*)
matter of figuring out why it's NULL.

* This is sarcasm.

-- 
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