LinuxLists.cc - ath5k misbehaving affecting other kernel parts unrelated?

2010-04-23 07:06:20

Subject: ath5k misbehaving affecting other kernel parts unrelated?

Greetings!

Is it possible a faulty ath5k module to affect diverse parts of kernel causing
different oopses to happen referencing things as different as cdrom_ioctl,
find_vma, i915_gem_object_get_pages, get_vfs_caps_from_disk,
warn_slowpath_common (ath5k_tasklet_rx), proc_lookup_de and
_spin_lock(ext4_getattr) [soft lookup]?

The task in which such errors happen is capturing packets with kismet during
the night. The errors aren't easy to create, sometimes they've already
happened when I check the computer in the morning and sometimes they require
stirring up the computer a bit such as starting X.

I memtested the machine during 7h and no error was detected.

I've been trying different kernels but main one is 2.6.32-21-generic, Ubuntu
flavour, with linux-backports-modules-wireless-lucid-generic installed. I would
use 2.6.34-rc5 vanilla if shutdown and suspend worked ;)

As such:
a) is it "normal"? I thought modules were somewhat isolated these days.
b) any advices for debugging? I've yet to have two oopses that are similar....

Thank you in Advance,
--
Pedro

2010-04-23 14:00:21

by John W. Linville

[permalink] [raw]

Subject: Re: ath5k misbehaving affecting other kernel parts unrelated?

On Fri, Apr 23, 2010 at 08:06:13AM +0100, Pedro Francisco wrote:
> Greetings!
>
> Is it possible a faulty ath5k module to affect diverse parts of kernel causing
> different oopses to happen referencing things as different as cdrom_ioctl,
> find_vma, i915_gem_object_get_pages, get_vfs_caps_from_disk,
> warn_slowpath_common (ath5k_tasklet_rx), proc_lookup_de and
> _spin_lock(ext4_getattr) [soft lookup]?
>
> The task in which such errors happen is capturing packets with kismet during
> the night. The errors aren't easy to create, sometimes they've already
> happened when I check the computer in the morning and sometimes they require
> stirring up the computer a bit such as starting X.
>
> I memtested the machine during 7h and no error was detected.
>
> I've been trying different kernels but main one is 2.6.32-21-generic, Ubuntu
> flavour, with linux-backports-modules-wireless-lucid-generic installed. I would
> use 2.6.34-rc5 vanilla if shutdown and suspend worked ;)
>
> As such:
> a) is it "normal"? I thought modules were somewhat isolated these days.
> b) any advices for debugging? I've yet to have two oopses that are similar....

It is certainly possible -- improper setup of DMA could be scribbling
over memory that doesn't belong to ath5k. That sort of thing can be
ugly to track-down...

You mentioned Kismet. Do you experience this sort of problem when
using ath5k for "normal" purposes (e.g. browsing the web)? Or only
when using it to monitor the network?

John
--
John W. Linville Someday the world will need a hero, and you
[email protected] might be all we have. Be ready.

2010-04-23 16:41:13

by Bob Copeland

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Subject: Re: ath5k misbehaving affecting other kernel parts unrelated?

On Fri, Apr 23, 2010 at 09:48:23AM -0400, John W. Linville wrote:
> > a) is it "normal"? I thought modules were somewhat isolated these days.
> > b) any advices for debugging? I've yet to have two oopses that are similar....

Advice for debugging: turn on slub/slab debug options, and possibly
kmemcheck. kmemcheck was very helpful for me last time I had such
a corruption issue.

--
Bob Copeland %% http://www.bobcopeland.com

2010-04-23 16:44:07

by Maciej Żenczykowski

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Subject: Re: ath5k misbehaving affecting other kernel parts unrelated?

Do you have more than ~2.5-3.5GB of ram (enough to make some ram
non-32-bit-DMA-accessible) with swiotlb enabled,
if such are you seeing "DMA: Out of SW-IOMMU space" kernel messages?

On Fri, Apr 23, 2010 at 09:37, <[email protected]> wrote:
> On Fri, Apr 23, 2010 at 09:48:23AM -0400, John W. Linville wrote:
>> > a) is it "normal"? I thought modules were somewhat isolated these days.
>> > b) any advices for debugging? I've yet to have two oopses that are similar....
>
> Advice for debugging: turn on slub/slab debug options, and possibly
> kmemcheck. kmemcheck was very helpful for me last time I had such
> a corruption issue.
>
> --
> Bob Copeland %% http://www.bobcopeland.com
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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>

2010-04-23 19:14:04

by Dan Carpenter

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A Quinta, 29 de Abril de 2010 08:17:00 Vegard Nossum escreveu:
> Most likely you need to disable "Optimize for size", under "General
> setup" in the main menu to make it appear. But it could also be one of
> the other dependencies; check the "Depends on" line of KMEMCHECK when
> you do the search.
>
>
> Vegard

It was "CONFIG_FUNCTION_TRACER" which was on; incidently, such dependency
doesn't appear in the "Depends on" line, had to do a web search.

Will post the results tomorrow, unless there aren't any.

--
Pedro

2010-04-30 18:32:16

by Vegard Nossum

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Subject: Re: ath5k misbehaving affecting other kernel parts unrelated?

> A Sexta, 23 de Abril de 2010 17:37:03 [email protected] escreveu:
> -snip
>> Advice for debugging: turn on slub/slab debug options, and possibly
>> kmemcheck. kmemcheck was very helpful for me last time I had such
>> a corruption issue.
>
> I can't seem to find the "kmemcheck: trap use of uninitialized memory" option
> in make menuconfig, section Kernel Hacking, though a search shows it should be
> there.

Most likely you need to disable "Optimize for size", under "General
setup" in the main menu to make it appear. But it could also be one of
the other dependencies; check the "Depends on" line of KMEMCHECK when
you do the search.

Vegard