Re: [PATCH] SCSI IOCTL: Check for device deletion [was Re:__elv_add_request OOPS]

From: Linus Torvalds
Date: Wed May 25 2011 - 19:15:26 EST


On Wed, May 25, 2011 at 4:00 PM, Parag Warudkar <parag.lkml@xxxxxxxxx> wrote:
>
> It doesn't seem to help. Machine locked up and I was dropped to text
> console. I could only capture the oops by a camera.

Hmm. That's a different oops. It is now in scsi_prep_state_check().

At the beginning of it too. You can't see the "Code: " line in the
pictures, but the only dereference I see there is "sdev" itself being
NULL. And %cr2 is 0x640, which would seem to agree (the 'sdev'
structure is absolutely disgustingly big, and sdev->sdev_state is
indeed at an offset in that region.

That 'sdev' comes from scsi_prep_fn() doing

struct scsi_device *sdev = q->queuedata;

is that queuedata perhaps cleared even if the queue itself stays
around due to refcounts?

Linus
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