From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Andrew Morton <akpm@osdl.org>
Subject: Re: 2.6.15-rc5-mm2: ehci_hcd crashes on load sometimes
Date: Mon, 12 Dec 2005 22:39:19 +0100
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Cc: linux-kernel@vger.kernel.org, linux-usb-devel@lists.sourceforge.net
References: <20051211041308.7bb19454.akpm@osdl.org> <200512122155.43632.rjw@sisk.pl> <20051212130957.146fbcc3.akpm@osdl.org>
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On Monday, 12 December 2005 22:09, Andrew Morton wrote:
> "Rafael J. Wysocki" <rjw@sisk.pl> wrote:
> >
> >  > It's best to actually send a copy of line 620 - kernels vary a lot, and
> >  > many developers won't have that particualr -mm tree handy.
> >  > 
> >  > The way I normally do this is to do `gdb vmlinux' and then `l
> >  > *0xffffffff880ad9d0'.
> > 
> >  Does it work for modules too?
> 
> Ah.  There are certainly ways of doing this - see the kgdb documentation. 
> Or you can work out the module load address, gdb the module and do the
> appropriate arithmetic I guess.
> 
> Generally I just statically link anything which I want to play with.

Still, the oops is from a module.  I could link it statically for debugging,
but then the address would be different to the one in the oops.

Anyway, please tell me if my reasoning was correct: I thought I couldn't
figure it out based on the absolute address, but I could use the
displacements.  Namely, it followed from the oops that the problem
occured at the address {:ehci_hcd:ehci_irq+224}, which is at the
offset 224 wrt ehci_irq, so I did:

gdb drivers/usb/host/ehci-hcd.o

In gdb I did:

info line ehci_irq

and it told me the address the line started at, so I added 224 to it and
got the line 620.
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