NPTL Thread lockup issue on ARMv7

[Khem Raj]

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