NPTL Thread lockup issue on ARMv7

[Khem Raj]

On Tue, Feb 1, 2011 at 8:17 AM, Carmelo AMOROSO <carmelo.amoroso at st.com> wrote:
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> On 2/1/2011 5:14 PM, Nitin Garg wrote:
>> Hope I created the patch correctly. Pls let me know if this is
>> incorrect, otherwise pls add it to repository.
>>
>> Thanks,
>> Nitin
>>
>
> Nitin,
> according to the comment by Thomas, I've understood that we already have
> a good implementation in the nptl path, it should be just the case to
> fix the buildsys to properly pick-up the right one.
>
> I will check... Khem ?

yes thats fine too it will fix nptl I thought moving it to common arm
would make it LT use it too but probably fixing just for nptl it
better
>
> Carmelo
>
>> On Tue, Feb 1, 2011 at 1:13 AM, Khem Raj <raj.khem at gmail.com> wrote:
>>  > On (01/02/11 00:32), Nitin Garg wrote:
>>  >> Recently we came accross an issue on ARMv7 processors while running
>>  >> multiple threads. If say 3 threads are running continuously, 1 or 2
>>  >> might get locked somewhere. If we attach gdb and run again, all 3
>>  >> threads start executing for a while and after some time 1 or 2 threads
>>  >> gets locked-up again. The backtrace showed the threads are stuck in
>>  >> __pthread_mutex_lock (atomic_compare_and_exchange_val_acq).
>>  >>
>>  >> We noticed that the atomic compare and exchange functions are not
>>  >> atomic for ARM. Once we added the Atomic compare and exchange
>>  >> function, the problem was resolved.
>>  >>
>>  >> Pls see below patch for review and kindly add it to next release.
>>  >
>>  > This looks ok to me but you have to send a properly formatted and
>>  > signed-off patch so it can be tested and included. Using git format-patch
>>  > and git send-email is your best bet
>>  >
>>  > -Khem
>>  >
>>
>
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