Re: PI BUG with -rt13

david singleton
2005-11-22T02:13:52Z

Dave Carlson has tried the patch and although it works better, he's
discovered another race in the exit path.

I'll start working on the exit path race fix now that I have the race
in down_futex
fixed.

Dave

On Nov 21, 2005, at 1:26 PM, Ingo Molnar wrote:

>
> * David Singleton <dsingleton@mvista.com> wrote:
>
>> Ingo,
>> here is a patch that provides the correct locking for the rt_mutex
>> backing the robust pthread_mutex. The patch also unifies the locking
>> for all the robust functions and adds support for pthread_mutexes on
>> the heap.
>
> thanks. Could you split up the patch into a fix and a 'heap' patch (at
> a
> minimum)?
>
> it's this portion of the 'heap' patch that looks problematic:
>
>> --- base/linux-2.6.14/include/linux/mm.h 2005-11-18
>> 20:36:53.000000000 -0800
>> +++ wip/linux-2.6.14/include/linux/mm.h 2005-11-21 10:51:19.000000000
>> -0800
>> @@ -109,6 +109,11 @@
>> #ifdef CONFIG_NUMA
>> struct mempolicy *vm_policy; /* NUMA policy for the VMA */
>> #endif
>> +#ifdef CONFIG_FUTEX
>> + int robust_init; /* robust initialized? */
>> + struct list_head robust_list; /* list of robust futexes in this vma
>> */
>> + struct semaphore robust_sem; /* semaphore to protect the list */
>> +#endif
>> };
>
> why is there per-vma info needed?
>
> Also, what testing did this patch have - should it solve Dinakar's
> problem(s)?
>
> Ingo