2013-03-12 01:14:08

by Andrew Cooks

[permalink] [raw]
Subject: Bug involving dynamic_debug and '-p' modifier

Hi Jason

When I specify a '-p' modifier in the dynamic debug options in the
kernel command line, I get a kernel panic during boot. The panic
happens after userspace starts doing graphical stuff, but I haven't
been able to pinpoint exactly what.

If I use '=_' instead of '-p', or boot to a recovery mode, or change
the modifier after booting using debugfs, the panic doesn't occur. For
example, booting to runlevel 3 with '=_', then flipping the same
modifier to first to '+p' and then to '-p', before starting X does not
result in a panic.

Booting to runlevel 3 (or even 1!), with '-p' results in a panic, but
'rdshell' is OK.

I also tried the Red Hat kernel (just because it's installed - I
haven't figured out how to tell the package manager that I don't want
a kernel). This also panics, but it says that '-p' is not supported.

Please let me know if you need me to do any other tests.

'-p', panic: http://pastebin.com/8yAcBQdY
'-p', rdshell, no panic: http://pastebin.com/Hi2a7BZA

--
a.


2013-03-12 02:28:56

by Andrew Cooks

[permalink] [raw]
Subject: Re: Bug involving dynamic_debug and '-p' modifier

On Tue, Mar 12, 2013 at 9:14 AM, Andrew Cooks <[email protected]> wrote:
> Hi Jason
>
> When I specify a '-p' modifier in the dynamic debug options in the
> kernel command line, I get a kernel panic during boot. The panic
> happens after userspace starts doing graphical stuff, but I haven't
> been able to pinpoint exactly what.
>
> If I use '=_' instead of '-p', or boot to a recovery mode, or change
> the modifier after booting using debugfs, the panic doesn't occur. For
> example, booting to runlevel 3 with '=_', then flipping the same
> modifier to first to '+p' and then to '-p', before starting X does not
> result in a panic.
>
> Booting to runlevel 3 (or even 1!), with '-p' results in a panic, but
> 'rdshell' is OK.
>
> I also tried the Red Hat kernel (just because it's installed - I
> haven't figured out how to tell the package manager that I don't want
> a kernel). This also panics, but it says that '-p' is not supported.
>
> Please let me know if you need me to do any other tests.
>
> '-p', panic: http://pastebin.com/8yAcBQdY
> '-p', rdshell, no panic: http://pastebin.com/Hi2a7BZA
>
> --
> a.

Jason's mail bounced, so redirecting to Jim Cromie, who made the most
recent significant changes to dynamic_debug...

2013-03-17 02:50:06

by Jason Baron

[permalink] [raw]
Subject: Re: Bug involving dynamic_debug and '-p' modifier

Hi Andrew,

Thanks for the bug report. I need to send a patch to update the maintainers
file...

Haven't had a chance to look into this yet. Will get back to you.

Thanks,

-Jason



On 03/11/2013 10:28 PM, Andrew Cooks wrote:
> On Tue, Mar 12, 2013 at 9:14 AM, Andrew Cooks <[email protected]> wrote:
>> Hi Jason
>>
>> When I specify a '-p' modifier in the dynamic debug options in the
>> kernel command line, I get a kernel panic during boot. The panic
>> happens after userspace starts doing graphical stuff, but I haven't
>> been able to pinpoint exactly what.
>>
>> If I use '=_' instead of '-p', or boot to a recovery mode, or change
>> the modifier after booting using debugfs, the panic doesn't occur. For
>> example, booting to runlevel 3 with '=_', then flipping the same
>> modifier to first to '+p' and then to '-p', before starting X does not
>> result in a panic.
>>
>> Booting to runlevel 3 (or even 1!), with '-p' results in a panic, but
>> 'rdshell' is OK.
>>
>> I also tried the Red Hat kernel (just because it's installed - I
>> haven't figured out how to tell the package manager that I don't want
>> a kernel). This also panics, but it says that '-p' is not supported.
>>
>> Please let me know if you need me to do any other tests.
>>
>> '-p', panic: http://pastebin.com/8yAcBQdY
>> '-p', rdshell, no panic: http://pastebin.com/Hi2a7BZA
>>
>> --
>> a.
> Jason's mail bounced, so redirecting to Jim Cromie, who made the most
> recent significant changes to dynamic_debug...
> --
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