From: Peter Zijlstra <peterz@infradead.org>
To: Valdis.Kletnieks@vt.edu
Cc: linux-kernel@vger.kernel.org
Subject: Re: Stupid futex question - 2.6.33-rc7-mmotm0210
Date: Thu, 18 Feb 2010 15:37:59 +0100 [thread overview]
Message-ID: <1266503879.26719.702.camel@laptop> (raw)
In-Reply-To: <10057.1266501862@localhost>
On Thu, 2010-02-18 at 09:04 -0500, Valdis.Kletnieks@vt.edu wrote:
> Kernel: x86_64 2.6.33-rc7-mmotm0210
>
> I'm debugging a problem where pulseaudio is getting killed with a SIGKILL
> out of the blue. It appears to be a problem where pulseaudio sets
> RLIMIT_RTTIME and the bound gets exceeded. Analysis with 'top' shows
> a short spike of 96% system time, and the tail end of strace shows this:
>
> [pid 25065] 01:50:20.371484 ioctl(28, USBDEVFS_CONTROL, 0x7fd3d76f630c) = 0 <0.000015>
> [pid 25065] 01:50:20.371548 ioctl(28, 0x40045532, 0x7fd3d76f636c) = 0 <0.000016>
> [pid 25065] 01:50:20.371611 open("/dev/snd/pcmC0D0p", O_RDWR|O_NONBLOCK|O_CLOEXEC <unfinished ...>
> [pid 25064] 01:50:20.371678 <... write resumed> ) = 8 <0.002104>
> [pid 25064] 01:50:20.371718 futex(0xc2ec00, FUTEX_WAIT_PRIVATE, 0, NULL <unfinished ...>
> [pid 25066] 01:50:21.408392 +++ killed by SIGKILL +++
> PANIC: handle_group_exit: 25066 leader 25064
> [pid 25065] 01:50:21.408442 +++ killed by SIGKILL +++
> PANIC: handle_group_exit: 25065 leader 25064
> 01:50:21.420354 +++ killed by SIGKILL +++
>
> thread 25064 apparently gets gunned down due to RTTIME because it spent a whole
> second in a futex() call - is it reasonable for futex() to not return for that
> long?
>
> In other words - kernel bug because futex() should return, or pulseaudio bug
> for not understanding futex() can snooze a while?
>
> If a kernel bug, anybody got a better idea than nuking the RLIMIT_RTTIME call,
> waiting for it to repeat (takes between 1 minute and 1 hour or so), and
> whomping it a few times with sysrq-T?
is that second spend in processing sysrq-t?
next prev parent reply other threads:[~2010-02-18 14:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-18 14:04 Stupid futex question - 2.6.33-rc7-mmotm0210 Valdis.Kletnieks
2010-02-18 14:37 ` Peter Zijlstra [this message]
2010-02-18 16:42 ` Valdis.Kletnieks
2010-02-18 17:01 ` Peter Zijlstra
2010-02-18 18:45 ` Thomas Gleixner
2010-02-19 4:08 ` Darren Hart
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