Re: Random process lockup on ARM board: alsa-lib-1.0.25, FUTEX_WAIT_PRIVATE

From: Huang Shijie
Date: Wed Mar 07 2012 - 21:29:12 EST


Hi,

On Thu, Mar 8, 2012 at 4:07 AM, Darren Hart <dvhart@xxxxxxxxxxxxxxx> wrote:
>
>
> On 02/29/2012 01:12 AM, Huang Shijie wrote:
>> Hi ,
>>
>> I meet a similar problem with the latest futex code.
>>
>> I play the video and the processes will hang at the futex.
>
> Are either of you able to bisect the kernel? At the very least can you

I finially found my arch/arm/include/asm/futex.h is not the
latest, so i updated the header.

And the futex issue is gone now. But a dataAbort issue appears, I am
not sure whether it caused by the futex patch.
I am debugging it now.


BR
Huang Shijie
> find two kernels where it works and where it does not?
>
> Hanging on FUTEX_WAIT_PRIVATE can be the symptom for higher level
> problems including userspace locking issues and race conditions.
>
> Huang, are you also on ARM?

Yes, FREESCALE imx6q platform.

BR
Huang Shijie
>
> --
> Darren
>
>>
>> BR
>> Huang Shijie
>>
>> On Fri, Feb 24, 2012 at 8:29 AM, Jonathan Andrews <jon@xxxxxxxxxxxxxxx> wrote:
>>> Using kernel 3.2.5 with alsa-lib 1.0.25, all compiled with generic
>>> Debian arm-linux-gnueabi toolchain.
>>>
>>> arm-linux-gnueabi-gcc (Debian 4.3.2-1.1) 4.3.2
>>> Was used to build kernel, alsa-lib and application.
>>>
>>> Changing gcc version, kernel version or alsa-lib version makes the
>>> problem worse or better, but ALL versions seem to suffer this problem. I
>>> have also seen it once on Intel (but only once so far).
>>>
>>> Something seeks broken at a lower layer than im using. ÂI simply don't
>>> have the skill to debug it.
>>>
>>> The hardware is a USB cm109 audio adapter, but the problem seems to show
>>> on more than this one driver.
>>>
>>> The audio application writing to alsa will freezes at random intervals,
>>> infrequent at the moment, last one was after runtime 20H 37M 29S. ÂTwo
>>> processes are running, one reading from the sound device and one writing
>>> to the sound device. I am not using threading or anything very clever
>>> just generic alsa functions.
>>>
>>> This is the only diagnostic I can generate so far as running the
>>> application under strace slows it to the point it no longer functions
>>> enough to generate the problem.
>>>
>>> ARM / # strace -p 417
>>> Process 417 attached - interrupt to quit
>>> futex(0x175734, FUTEX_WAIT_PRIVATE, 2, NULL^C <unfinished ...>
>>> Process 417 detached
>>>
>>> ARM / # uname -a
>>> Linux (none) 3.2.5 #2 Wed Feb 22 17:11:52 GMT 2012 armv4tl GNU/Linux
>>> ARM / # uptime
>>> Â22:36:19 up 22:36, Â0 users, Âload average: 0.15, 0.16, 0.18
>>> ARM / # cat /proc/cpuinfo
>>> Processor    : ARM920T rev 0 (v4l)
>>> BogoMIPS Â Â Â Â: 199.06
>>> Features    Â: swp half thumb crunch
>>> CPU implementer : 0x41
>>> CPU architecture: 4T
>>> CPU variant   : 0x1
>>> CPU part    Â: 0x920
>>> CPU revision  Â: 0
>>>
>>>
>>> Any help welcome.
>>>
>>> Thanks,
>>> Jon
>>>
>>>
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>
> --
> Darren Hart
> Intel Open Source Technology Center
> Yocto Project - Linux Kernel
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