Re: 2.5.44 (now 2.5.46-c929): Strange oopses triggered by .

Re: 2.5.44 (now 2.5.46-c929): Strange oopses triggered by .

[Petr Vandrovec]

On  6 Nov 02 at 23:09, Petr Vandrovec wrote:
> 
> I'm getting really nervous :-( Is kdb able to track who caused unbalanced
> in_atomic() incrementation? 
> 
> After more than week of stable system I run simple 
> "arp vanicka.vc.cvut.cz" few minutes ago, and after arp output I got 
> sleeping function called from illegal context, quickly followed by two
> scheduling while atomic, and finally it died because of userspace faults 
> when in_atomic() is != 0 are treated as kernel ones...
> 
> As I saw nobody else reporting this or simillar problem, I'll start
> looking at e100 driver I use. Maybe it did not occured because of I
> was running -acX kernels since 25th Oct until yesterday. Anybody knows?

-acX use special stack for hardware IRQs, and preempt_count() is
copied only from task -> hwirq, not other way around (because of it
assumes that preempt_count() is same on exit as it was on enter...).
That's probably reason why -acX was working for me almost two weeks,
but as soon as I returned back to non-ac, it died.
                                                    Petr Vandrovec
                                                    vandrove@vc.cvut.cz
                                                    

Preempt count check when leaving IRQ? (Was: Re: 2.5.44 (now 2.5.46-c929): Strange oopses triggered by .)

[Roger Larsson]

On Wednesday 06 November 2002 22.49, Petr Vandrovec wrote:
> On  6 Nov 02 at 23:09, Petr Vandrovec wrote:
> > 
> > I'm getting really nervous :-( Is kdb able to track who caused unbalanced
> > in_atomic() incrementation? 
> > 
> > After more than week of stable system I run simple 
> > "arp vanicka.vc.cvut.cz" few minutes ago, and after arp output I got 
> > sleeping function called from illegal context, quickly followed by two
> > scheduling while atomic, and finally it died because of userspace faults 
> > when in_atomic() is != 0 are treated as kernel ones...
> > 
> > As I saw nobody else reporting this or simillar problem, I'll start
> > looking at e100 driver I use. Maybe it did not occured because of I
> > was running -acX kernels since 25th Oct until yesterday. Anybody knows?
> 
> -acX use special stack for hardware IRQs, and preempt_count() is
> copied only from task -> hwirq, not other way around (because of it
> assumes that preempt_count() is same on exit as it was on enter...).
> That's probably reason why -acX was working for me almost two weeks,
> but as soon as I returned back to non-ac, it died.
>                                                     Petr Vandrovec
>                                                     vandrove@vc.cvut.cz
>                                                     

This is another CHECK to do then.

Make a copy of preempt count when entering an IRQ.
Check that we have the same value when leaving.
(using -acX we only have to add the check when leaving)

/RogerL

-- 
Roger Larsson
Skellefteå
Sweden

Re: 2.5.44 (now 2.5.46-c929): Strange oopses triggered by ...

[Petr Vandrovec]

On 25 Oct 02 at 11:19, Petr Vandrovec wrote:
> On 23 Oct 02 at 17:57, Petr Vandrovec wrote:
> 
> > Hi,
> >   I just left my 2.5.44 box unattended for hour and half, and when
> > I came back, I saw very strange things on screen:
> 
> Machine did it again yesterday 7:55 morning, after having ~10 hours
> uptime. All three dumps are same, with minor difference in last one:
> *pde is 024c4067, and Process line is 'cat (pid: 11497, threadinfo=c3960000,
> task=d1c3a780)'... All other values are same.

I'm getting really nervous :-( Is kdb able to track who caused unbalanced
in_atomic() incrementation? 

After more than week of stable system I run simple 
"arp vanicka.vc.cvut.cz" few minutes ago, and after arp output I got 
sleeping function called from illegal context, quickly followed by two
scheduling while atomic, and finally it died because of userspace faults 
when in_atomic() is != 0 are treated as kernel ones...

As I saw nobody else reporting this or simillar problem, I'll start
looking at e100 driver I use. Maybe it did not occured because of I
was running -acX kernels since 25th Oct until yesterday. Anybody knows?
                                                Thanks,
                                                    Petr Vandrovec
                                                    vandrove@vc.cvut.cz

Debug: sleeping function called from illegal context at include/asm/semaphore.h:119
Call Trace:
   [..........] __might_sleep+0x43/0x47
   [..........] seq_read
   ...........  vfs_read
   ...........  sys_read
   [..........] syscall_call+0x7/0xb
  
bad: scheduling while atomic!
   [..........] schedule
   ............ sys_read
   [..........] work_resched
   
bad: scheduling while atomic!
   [..........] schedule
   ............ sys_munmap
   [..........] work_resched

Unable to handle kernel paging request...

...
EIP: 0x4004DB65
...
Process: arp