Messages in this thread | | | Subject | Stupid futex question - 2.6.33-rc7-mmotm0210 | From | Valdis.Kletnieks@vt ... | Date | Thu, 18 Feb 2010 09:04:22 -0500 |
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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?
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