* preempt_rt bug or warn on arm v4t
@ 2007-04-20 11:06 Manfred Gruber
2007-04-20 13:01 ` Jan Altenberg
0 siblings, 1 reply; 4+ messages in thread
From: Manfred Gruber @ 2007-04-20 11:06 UTC (permalink / raw)
To: linux-kernel; +Cc: jan.altenberg, tglx, mingo
Hi !
I am using 2.6.21-rc7 with Preempt_rt Patch 2.6.20-rc6-rt0 on ep93xx.
This oops does not trigger in preempt_rt patch is applied.
On startup i get following oops when preemption is none.
Mount-cache hash table entries: 512
CPU: Testing write buffer coherency: ok
BUG: at kernel/sched.c:4285 __schedule()
[<c006d404>] (dump_stack+0x0/0x14) from [<c02eeea4>] (__schedule+0x844/0x8e0)
[<c02ee660>] (__schedule+0x0/0x8e0) from [<c02ef038>] (schedule+0xd0/0x118)
[<c02eef68>] (schedule+0x0/0x118) from [<c02ef3e0>]
(wait_for_completion+0x94/0xf0)
r4 = C042DE88
[<c02ef34c>] (wait_for_completion+0x0/0xf0) from [<c0099c14>]
(keventd_create_kthread+0x3c/0x74)
r7 = 00000000 r6 = 00000002 r5 = C042DED4 r4 = C042DF18
[<c0099bd8>] (keventd_create_kthread+0x0/0x74) from [<c0099ccc>]
(kthread_create+0x80/0xc8)
r6 = C001C320 r5 = C042DED4 r4 = 00000000
[<c0099c4c>] (kthread_create+0x0/0xc8) from [<c009ad48>]
(posix_cpu_thread_call+0x40/0xb8)
r3 = 00000000 r2 = C0352BD0
r5 = 00000000 r4 = 00000000
[<c009ad08>] (posix_cpu_thread_call+0x0/0xb8) from [<c000dd10>]
(posix_cpu_thread_init+0x24/0x40)
r5 = 00000000 r4 = C03A7F74
[<c000dcec>] (posix_cpu_thread_init+0x0/0x40) from [<c00088b0>]
(init+0x38/0x30c)
r4 = 00000000
[<c0008878>] (init+0x0/0x30c) from [<c0087b90>] (do_exit+0x0/0x80c)
NET: Registered protocol family 16
ep93xx: PLL1 running at 400 MHz, PLL2 at 192 MHz
ep93xx: FCLK 200 MHz, HCLK 100 MHz, PCLK 50 MHz
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
If I enable full preemp_rt i get a warn:
irq event stamp: 0
hardirqs last enabled at (0): [<00000000>] __init_begin+0x3fff8000/0x30
hardirqs last disabled at (0): [<c00850f4>] copy_process+0x344/0x124c
softirqs last enabled at (0): [<c00850f4>] copy_process+0x344/0x124c
softirqs last disabled at (0): [<00000000>] __init_begin+0x3fff8000/0x30
BUG: at kernel/sched.c:4288 __schedule()
[<c006e71c>] (dump_stack+0x0/0x28) from [<c0308b64>] (__schedule+0xa04/0xab4)
[<c0308160>] (__schedule+0x0/0xab4) from [<c0308e28>] (schedule+0xdc/0x128)
[<c0308d4c>] (schedule+0x0/0x128) from [<c009d760>] (kthread+0xcc/0x12c)
r4 = C0B72000
[<c009d694>] (kthread+0x0/0x12c) from [<c008a508>] (do_exit+0x0/0x814)
r7 = 00000000 r6 = 00000000 r5 = 00000000 r4 = 00000000
---------------------------
| preempt count: 00000000 ]
| 0-level deep critical section nesting:
Does someone has an idea what is wrong ?
The configs can be found here:
https://dev.contec.at/dev/micro/micro9/LINUX/trunk/kernel/linux-2.6-config/
My quilt queue can be found here:
https://dev.contec.at/dev/micro/micro9/LINUX/trunk/kernel/linux-2.6/patches/
thanks regards
manfred
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: preempt_rt bug or warn on arm v4t
2007-04-20 11:06 preempt_rt bug or warn on arm v4t Manfred Gruber
@ 2007-04-20 13:01 ` Jan Altenberg
2007-04-20 13:26 ` Manfred Gruber
0 siblings, 1 reply; 4+ messages in thread
From: Jan Altenberg @ 2007-04-20 13:01 UTC (permalink / raw)
To: Manfred Gruber; +Cc: linux-kernel, tglx, mingo
Hi Manfred,
> I am using 2.6.21-rc7 with Preempt_rt Patch 2.6.20-rc6-rt0 on ep93xx.
Do you mean 2.6.21-rc6-rt0?
> This oops does not trigger in preempt_rt patch is applied.
It does only appear, when the preempt_rt patch is applied. Did I get you
right?
> On startup i get following oops when preemption is none.
>
> Mount-cache hash table entries: 512
> CPU: Testing write buffer coherency: ok
> BUG: at kernel/sched.c:4285 __schedule()
> [<c006d404>] (dump_stack+0x0/0x14) from [<c02eeea4>] (__schedule+0x844/0x8e0)
> [<c02ee660>] (__schedule+0x0/0x8e0) from [<c02ef038>] (schedule+0xd0/0x118)
> [<c02eef68>] (schedule+0x0/0x118) from [<c02ef3e0>]
> (wait_for_completion+0x94/0xf0)
> r4 = C042DE88
> [<c02ef34c>] (wait_for_completion+0x0/0xf0) from [<c0099c14>]
> (keventd_create_kthread+0x3c/0x74)
> r7 = 00000000 r6 = 00000002 r5 = C042DED4 r4 = C042DF18
> [<c0099bd8>] (keventd_create_kthread+0x0/0x74) from [<c0099ccc>]
> (kthread_create+0x80/0xc8)
> r6 = C001C320 r5 = C042DED4 r4 = 00000000
> [<c0099c4c>] (kthread_create+0x0/0xc8) from [<c009ad48>]
> (posix_cpu_thread_call+0x40/0xb8)
> r3 = 00000000 r2 = C0352BD0
> r5 = 00000000 r4 = 00000000
> [<c009ad08>] (posix_cpu_thread_call+0x0/0xb8) from [<c000dd10>]
> (posix_cpu_thread_init+0x24/0x40)
> r5 = 00000000 r4 = C03A7F74
> [<c000dcec>] (posix_cpu_thread_init+0x0/0x40) from [<c00088b0>]
> (init+0x38/0x30c)
> r4 = 00000000
> [<c0008878>] (init+0x0/0x30c) from [<c0087b90>] (do_exit+0x0/0x80c)
This WARN_ON in __schedule seems to be triggered:
if (!irqs_disabled()) {
static int once = 1;
if (once) {
once = 0;
print_irqtrace_events(current);
WARN_ON(1);
}
}
I've seen this on an Atmel AT91SAM9261EK board a few days ago, when I
was implementing GENERIC_TIME and GENERIC_CLOCKEVENTS. I've tested with
2.6.20-rt8 and 2.6.21-rc6-rt0.
(an early version of the patch can be found here:
http://www.tglx.de/private/jan/at91sam/at91sam9260-generic-time-2.6.21-rc6-rt0.diff)
Jan
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: preempt_rt bug or warn on arm v4t
2007-04-20 13:01 ` Jan Altenberg
@ 2007-04-20 13:26 ` Manfred Gruber
2007-04-25 15:02 ` Manfred Gruber
0 siblings, 1 reply; 4+ messages in thread
From: Manfred Gruber @ 2007-04-20 13:26 UTC (permalink / raw)
To: linux-kernel; +Cc: tglx, mingo
hi jan !
Am Freitag, 20. April 2007 15:01 schrieben Sie:
> > I am using 2.6.21-rc7 with Preempt_rt Patch 2.6.20-rc6-rt0 on ep93xx.
>
> Do you mean 2.6.21-rc6-rt0?
sorry yes 2.6.21-rc6-rt0.
> > This oops does not trigger in preempt_rt patch is applied.
>
> It does only appear, when the preempt_rt patch is applied. Did I get you
> right?
correct
regards manfred
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: preempt_rt bug or warn on arm v4t
2007-04-20 13:26 ` Manfred Gruber
@ 2007-04-25 15:02 ` Manfred Gruber
0 siblings, 0 replies; 4+ messages in thread
From: Manfred Gruber @ 2007-04-25 15:02 UTC (permalink / raw)
To: linux-kernel; +Cc: tglx, Jan Altenberg, Ingo Molnar
Hi !
Gerrit Binnenmars pointed out that others have the same problem:
http://linux.omap.com/pipermail/linux-omap-open-source/2007-April/009535.html:
http://article.gmane.org/gmane.linux.distributions.gumstix.general/21376/match=gumstix+realtime+bug+sched+c
Jan Altenberg showed me that in include/asm-arm/system.h I should comment out
this line:
#define __ARCH_WANT_INTERRUPTS_ON_CTXSW
Without this line, irqs are disabled on context switches. But this is only a
change that the WARN dose not more occure. Is this now a hack or the
sollution? Hopfully some RT hacker can look deeper, and find what is wrong.
thanks
regards manfred
Am Freitag, 20. April 2007 15:26 schrieben Sie:
> hi jan !
>
> Am Freitag, 20. April 2007 15:01 schrieben Sie:
> > > I am using 2.6.21-rc7 with Preempt_rt Patch 2.6.20-rc6-rt0 on ep93xx.
> >
> > Do you mean 2.6.21-rc6-rt0?
>
> sorry yes 2.6.21-rc6-rt0.
>
> > > This oops does not trigger in preempt_rt patch is applied.
> >
> > It does only appear, when the preempt_rt patch is applied. Did I get you
> > right?
>
> correct
>
> regards manfred
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^ permalink raw reply [flat|nested] 4+ messages in thread
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2007-04-20 11:06 preempt_rt bug or warn on arm v4t Manfred Gruber
2007-04-20 13:01 ` Jan Altenberg
2007-04-20 13:26 ` Manfred Gruber
2007-04-25 15:02 ` Manfred Gruber
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