Re: 2.6.19-rc6-mm2 hangs when gdb is run on a multithread program

Jeremy Fitzhardinge
2006-12-11T01:45:34Z

walt wrote:
> Jeremy Fitzhardinge wrote:
>
>> Pedro Larroy Tovar wrote:
>>
>>> Hi
>>>
>>> I can reproduce a crash with 2.6.19-rc6-mm2 triggered when debugging a
>>> program with gdb that uses pthreads. No oops or anything strange seems
>>> to be printed by the kernel, but the box appears to stop doing disk IO.
>>>
>
>
>> Hm, I wonder if this is related walt's problem running things under gdb?
>>
>
> Jeremy, I redid my git-bisect from scratch and came up with a different
> commit for the gdb breakage:
>
> commit f95d47caae5302a63d92be9a0292abc90e2a14e1
> Author: Jeremy Fitzhardinge <jeremy@goop.org>
> Date: Thu Dec 7 02:14:02 2006 +0100
> [PATCH] i386: Use %gs as the PDA base-segment in the kernel
>
> This commit is the one which causes gdb to halt with this error
> no matter what executable I try to run:
> Warning:
> Cannot insert breakpoint -2.
> Error accessing memory address 0xd74b: Input/output error.
>
> I tried to git-revert just this one commit, but I get merge conflicts
> I don't how to resolve.
>
> BTW, I just discovered tons of kernel debugging config options which
> were turned off -- I just turned several of them on. Maybe I can give
> you better info now.
>

OK, this is the changeset I'd expect to cause problems. I'll try to
repo it here.

J