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

[Darren Hart <dvhart@linux.intel.com>]

On 03/07/2012 08:24 PM, Huang Shijie wrote:
> hi,
> 
> On Thu, Mar 8, 2012 at 11:36 AM, Darren Hart <dvhart@linux.intel.com> wrote:
>>
>>
>> On 03/07/2012 06:28 PM, Huang Shijie wrote:
>>> Hi,
>>>
>>> On Thu, Mar 8, 2012 at 4:07 AM, Darren Hart <dvhart@linux.intel.com> 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().

You are calling the futex syscall directly from your application?

--
Darren

> 
> 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@jonshouse.co.uk> 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.  I 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.  Two
>>>>>> 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
>>>>>>  22:36:19 up 22:36,  0 users,  load average: 0.15, 0.16, 0.18
>>>>>> ARM / # cat /proc/cpuinfo
>>>>>> Processor       : ARM920T rev 0 (v4l)
>>>>>> BogoMIPS        : 199.06
>>>>>> Features        : swp half thumb crunch
>>>>>> CPU implementer : 0x41
>>>>>> CPU architecture: 4T
>>>>>> CPU variant     : 0x1
>>>>>> CPU part        : 0x920
>>>>>> CPU revision    : 0
>>>>>>
>>>>>>
>>>>>> Any help welcome.
>>>>>>
>>>>>> Thanks,
>>>>>> Jon
>>>>>>
>>>>>>
>>>>>> --
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>>>>> --
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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

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