Re: [Regression] 2.6.24-git9: RT sched mishandles artswrapper (bisected)

Dmitry Adamushko
2008-02-05T21:46:41Z

Rafael, any progress with this issue? (a few questions below).

> >
> > Does this artsmessage thing also run with RT priority?
>
> Well, it's in a strange state (after it's broken). From top:
>
> PR = -51
> NI = 0
> S = R
> %CPU = 0.0
> %MEM = 0.0

cat /proc/$PID/stat ; sleep 3; cat /proc/$PID/stat ?
cat /proc/sched_debug; sleep 3 ; cat /proc/sched_debug

and also cat /proc/$PID/stat taken when this task still looks 'sane' :-/

Do you mean that only SCHED_NORMAL tasks can't run on this cpu or RT
tasks of high prio as well (so that maybe the scheduler is in
inconsistent state) ?
If the latter, the watchdog should have triggered after a while (if
enabled), I guess.

>
> Here's the corresponding trace from sysrq+t:
>
> [<ffffffff8022fdb7>] ? try_to_wake_up+0x77/0x200
> [<ffffffff8023573d>] __cond_resched+0x2d/0x60
> [<ffffffff804ddce1>] _cond_resched+0x31/0x40
> [<ffffffff804ddd24>] wait_for_common+0x34/0x170
> [<ffffffff8022fdb7>] ? try_to_wake_up+0x77/0x200
> [<ffffffff804ddec8>] wait_for_completion+0x18/0x20
> [ ... ]

does a stack trace always look like this?

--
Best regards,
Dmitry Adamushko