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

[Huang Shijie]

hi,

On Thu, Mar 8, 2012 at 11:36 AM, Darren Hart <dvhart@xxxxxxxxxxxxxxx> wrote:
>
>
> On 03/07/2012 06:28 PM, Huang Shijie wrote:
>> 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.
>
> Just make sure it matches your kernel version.
>
>>
>> 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.
>
> Which APIs are you using that make the futex syscall?
>

futex_wait().

I cherry-pick the
" df77abc ARM: 7099/1: futex: preserve oldval in SMP
__futex_atomic_op" to the arch/arm/include/asm/futex.h.


BR
Huang Shijie

> --
> Darren
>
>>
>>
>> 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
>
> --
> Darren Hart
> Intel Open Source Technology Center
> Yocto Project - Linux Kernel
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