Re: [PING][PATCH] Fix race in pthread_mutex_lock while promoting to PTHREAD_MUTEX_ELISION_NP [BZ #23275]

[Stefan Liebler <stli@linux.ibm.com>]

PING

On 08/27/2018 11:12 AM, Stefan Liebler wrote:
> PING
> Can anybody have a look, please?
> 
> On 07/30/2018 09:21 AM, Stefan Liebler wrote:
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>> On 07/23/2018 08:42 AM, Stefan Liebler wrote:
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>>> Please have a look at the patch posted here:
>>> https://www.sourceware.org/ml/libc-alpha/2018-06/msg00246.html
>>>
>>> On 07/16/2018 01:56 PM, Stefan Liebler wrote:
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>>>>
>>>> On 07/10/2018 08:33 AM, Stefan Liebler wrote:
>>>>> PING
>>>>>
>>>>> On 07/03/2018 08:28 AM, Stefan Liebler wrote:
>>>>>> PING
>>>>>>
>>>>>> On 06/26/2018 08:45 AM, Stefan Liebler wrote:
>>>>>>> PING
>>>>>>>
>>>>>>> On 06/19/2018 09:45 AM, Stefan Liebler wrote:
>>>>>>>> PING
>>>>>>>>
>>>>>>>> On 06/12/2018 04:24 PM, Stefan Liebler wrote:
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> The race leads either to pthread_mutex_destroy returning EBUSY 
>>>>>>>>> or triggering an assertion (See description in bugzilla).
>>>>>>>>>
>>>>>>>>> This patch is fixing the race by ensuring that the elision path 
>>>>>>>>> is used in all cases if elision is enabled by the 
>>>>>>>>> GLIBC_TUNABLES framework.
>>>>>>>>>
>>>>>>>>> The __kind variable in struct __pthread_mutex_s is accessed 
>>>>>>>>> concurrently. Therefore we are now using the atomic macros.
>>>>>>>>>
>>>>>>>>> The new testcase tst-mutex10 is triggering the race on s390x 
>>>>>>>>> and intel. Presumably also on power, but I don't have access to 
>>>>>>>>> a power machine with lock-elision. At least the code for power 
>>>>>>>>> is the same as on the other two architectures. Can somebody 
>>>>>>>>> test it on power?
>>>>>>>>>
>>>>>>>>> Bye
>>>>>>>>> Stefan
>>>>>>>>>
>>>>>>>>> ChangeLog:
>>>>>>>>>
>>>>>>>>>      [BZ #23275]
>>>>>>>>>      * nptl/tst-mutex10.c: New File.
>>>>>>>>>      * nptl/Makefile (tests): Add tst-mutex10.
>>>>>>>>>      (tst-mutex-ENV): New variable.
>>>>>>>>>      * sysdeps/unix/sysv/linux/s390/force-elision.h: 
>>>>>>>>> (FORCE_ELISION):
>>>>>>>>>      Ensure that elision path is used if elision is available.
>>>>>>>>>      * sysdeps/unix/sysv/linux/powerpc/force-elision.h
>>>>>>>>>      (FORCE_ELISION): Likewise.
>>>>>>>>>      * sysdeps/unix/sysv/linux/x86/force-elision.h: 
>>>>>>>>> (FORCE_ELISION):
>>>>>>>>>      Likewise.
>>>>>>>>>      * nptl/pthreadP.h (PTHREAD_MUTEX_TYPE,
>>>>>>>>>      PTHREAD_MUTEX_TYPE_ELISION, PTHREAD_MUTEX_PSHARED):
>>>>>>>>>      Use atomic_load_relaxed.
>>>>>>>>>      * nptl/pthread_mutex_consistent.c (pthread_mutex_consistent):
>>>>>>>>>      Likewise.
>>>>>>>>>      * nptl/pthread_mutex_getprioceiling.c
>>>>>>>>>      (pthread_mutex_getprioceiling): Likewise.
>>>>>>>>>      * nptl/pthread_mutex_lock.c (__pthread_mutex_lock_full,
>>>>>>>>>      __pthread_mutex_cond_lock_adjust): Likewise.
>>>>>>>>>      * nptl/pthread_mutex_setprioceiling.c
>>>>>>>>>      (pthread_mutex_setprioceiling): Likewise.
>>>>>>>>>      * nptl/pthread_mutex_timedlock.c (__pthread_mutex_timedlock):
>>>>>>>>>      Likewise.
>>>>>>>>>      * nptl/pthread_mutex_trylock.c (__pthread_mutex_trylock):
>>>>>>>>>      Likewise.
>>>>>>>>>      * nptl/pthread_mutex_unlock.c (__pthread_mutex_unlock_full):
>>>>>>>>>      Likewise.
>>>>>>>>>      * sysdeps/nptl/bits/thread-shared-types.h
>>>>>>>>>      (struct __pthread_mutex_s): Add comments.
>>>>>>>>>      * nptl/pthread_mutex_destroy.c (__pthread_mutex_destroy):
>>>>>>>>>      Use atomic_load_relaxed and atomic_store_relaxed.
>>>>>>>>>      * nptl/pthread_mutex_init.c (__pthread_mutex_init):
>>>>>>>>>      Use atomic_store_relaxed.
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>