RE: [microblaze-uclinux] kernel BUG at sched.c:687!

[Brettschneider Falk <fbrettschneider@xxxxxxxxxxxxxxxxx>]

Hi,

as soon as I strip it down to a test case I don't hit the bad time frame
anymore.
The kernel is from middle of November 05, after you changed the entry.S
stuff. I haven't seen changes in arch/microblaze/kernel after that. The file
sched.c wasn't changed since ages.

Now I sometimes also see the output:
kernel BUG at sched.c:562!

Furthermore I've seen crashes of the program and the last output was logging
from a logically completely senseless function of my program, instead of
switching the thread.

Cheers,
F@lk


> -----Original Message-----
> From: owner-microblaze-uclinux@xxxxxxxxxxxxxx
> [mailto:owner-microblaze-uclinux@xxxxxxxxxxxxxx]On Behalf Of John
> Williams
> Sent: Friday, February 17, 2006 9:02 AM
> To: microblaze-uclinux@xxxxxxxxxxxxxx
> Subject: Re: [microblaze-uclinux] kernel BUG at sched.c:687!
> 
> 
> Hi Falk,
> 
> If you can produce a minimal test case that demonstrates the 
> behaviour,
> I'll take a look at it.  I realise this may be tricky, but 
> isolating it
> is half the battle, before fixing it.
> 
> I believe the platform context switch code to be correct.  There was a
> bug fix that I checked in in Nov/Dec last year - I assume you are
> running on latest kernel sources?
> 
> Regards,
> 
> John
> 
> Brettschneider Falk wrote:
> > Hi,
> > I have 4 pthreads with SCHED_RR and different priorities 
> and when a certain
> > thread is killed due a timeout, I sometimes get 
> > 	kernel BUG at sched.c:687!
> > and usually just a Linux crash. This all only happens if 
> many context
> > switches happen during the killing of that pthread. All 
> threads heavily use
> > mutexes, semaphores and 1 of them uses poll() to wait for 
> events of a kernel
> > driver.
> > 
> > Are you sure the microblaze's platform code for context 
> switches is really
> > OK?
> > Otherwise I wish we used kernel 2.6.
> > 
> > Once I thought I worked around such scheduler problems by 
> using pthread_join
> > to catch a dying thread but now I often hit a time frame 
> where that doesn't
> > help either.
> > 
> > I've played around with some ideas for workaround for the 
> last 5 days but
> > now I'm stranded again. *sigh*
> > 
> > Cheers
> > F@lk
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