Re: [BUG] usb-storage: Error in queuecommand: us->srb = ffff88006a338480

[Brian Kysela <brian.kysela@gmail.com>]

On 2008-11-05 at 17:49 -0800, Andrew Morton wrote: 
> On Thu, 30 Oct 2008 17:35:57 -0400
> Brian Kysela <bkysela@gmail.com> wrote:
> 
> > On kernels ranging from 2.6.26 - 2.6.28-rc2
> 
> So 2.6.25 was OK?

I had only tested back to 2.6.26. If I have time and find a kernel
before that that works consistently, I'll let you know.

> 
> > on an Intel P4 3.2GHz HT x86-64
> > cpu, I am seeing a bug that occurs about half the time when copying ~300MB
> > data from a usb flash drive (FAT) to hard drive (XFS). There are three
> > possible outcomes, so far, when I hit the bug:
> > 
> >     (1) The copy process hangs, cpu wait hits 100% and load avg climbs until
> >         reboot;
> >     (2) The copy process hangs and then recovers and then one of:
> >         (a) the cpu wait & load avg both decline to normal; or
> >         (b) cpu wait hovers at 100% and the load avg slowly climbs until reboot;
> >     (3) Kernel bug reported and machine locks up.
> > 
> > Result (1) is the most frequent. Result (3) happened only twice out of about 40
> > tests. I lose the full traces, but here are two relevant lines that I see on
> > screen before the machine locks up:
> > 
> > kernel BUG at /home/brian/linux-2.6/block/elevator.c:841!
> > invalid opcode: 0000 [#1] PREMPT SMP
> 
> It is unclear what kernel version produced that message, and that is
> important information.  In 2.6.28-rc2, block/elevator.c:841 is
> 
>     void elv_dequeue_request(struct request_queue *q, struct request *rq)
>     {
> -->>	BUG_ON(list_empty(&rq->queuelist));
> 	BUG_ON(ELV_ON_HASH(rq));
> 
> please confirm that I have the correct line there.

Yes, that's the correct line, it was 2.6.28-rc2 that produced those.
I'll try usbmon per Alan Stern's suggestion and see if that shows
anything interesting.

Brian