lkml.org 
[lkml]   [2013]   [Mar]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: intel_pstate_timer_func divide by zero oops
From
On Wed, Mar 27, 2013 at 10:51 PM, Dirk Brandewie
<dirk.brandewie@gmail.com> wrote:
>
> Is there any way to capture the beginning of this trace?

I tried but since the oops scrolls fast followed by a hard freeze, I
wasn't able to capture it completely.
May be I can try netconsole and see if that helps.

>
> pid_param_set() is on the stack which means that something is changing
> the debugfs parameters or the stack is FUBAR.
>
I somehow doubt the stack is messed up as the call traces are always identical.
(pid_param_set() seems to be in first trace as well.)

>
> I don't see how duration_us can be zero unless somehow I am getting
> back-to-back
> timer callbacks which seems unlikely since the timer is not re-armed until
> the timer function is about to return and the driver has done all its work
> for the sample period

Do the two oops with common call stack suggest back to back callbacks?

I will add some debugging checks tomorrow to see what is going on. But
sounds like a minimal fix would be to guard against callbacks in quick
succession?
i.e. return from sample if ktime_us_delta(now, cpu->prev_sample) is zero?

Thanks,
Parag


\
 
 \ /
  Last update: 2013-03-28 04:41    [W:0.061 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site