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

[Stefan Liebler]

PING
Can anybody have a look, please?

On 07/30/2018 09:21 AM, Stefan Liebler wrote:
> PING
> On 07/23/2018 08:42 AM, Stefan Liebler wrote:
>> PING
>> 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:
>>> PING
>>>
>>> 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:
>>>>>>>>
>>>>>>>> Â Â Â Â Â [BZ #23275]
>>>>>>>> Â Â Â Â Â * nptl/tst-mutex10.c: New File.
>>>>>>>> Â Â Â Â Â * nptl/Makefile (tests): Add tst-mutex10.
>>>>>>>> Â Â Â Â Â (tst-mutex-ENV): New variable.
>>>>>>>> Â Â Â Â Â * sysdeps/unix/sysv/linux/s390/force-elision.h: 
>>>>>>>> (FORCE_ELISION):
>>>>>>>> Â Â Â Â Â Ensure that elision path is used if elision is available.
>>>>>>>> Â Â Â Â Â * sysdeps/unix/sysv/linux/powerpc/force-elision.h
>>>>>>>> Â Â Â Â Â (FORCE_ELISION): Likewise.
>>>>>>>> Â Â Â Â Â * sysdeps/unix/sysv/linux/x86/force-elision.h: 
>>>>>>>> (FORCE_ELISION):
>>>>>>>> Â Â Â Â Â Likewise.
>>>>>>>> Â Â Â Â Â * nptl/pthreadP.h (PTHREAD_MUTEX_TYPE,
>>>>>>>> Â Â Â Â Â PTHREAD_MUTEX_TYPE_ELISION, PTHREAD_MUTEX_PSHARED):
>>>>>>>> Â Â Â Â Â Use atomic_load_relaxed.
>>>>>>>> Â Â Â Â Â * nptl/pthread_mutex_consistent.c (pthread_mutex_consistent):
>>>>>>>> Â Â Â Â Â Likewise.
>>>>>>>> Â Â Â Â Â * nptl/pthread_mutex_getprioceiling.c
>>>>>>>> Â Â Â Â Â (pthread_mutex_getprioceiling): Likewise.
>>>>>>>> Â Â Â Â Â * nptl/pthread_mutex_lock.c (__pthread_mutex_lock_full,
>>>>>>>> Â Â Â Â Â __pthread_mutex_cond_lock_adjust): Likewise.
>>>>>>>> Â Â Â Â Â * nptl/pthread_mutex_setprioceiling.c
>>>>>>>> Â Â Â Â Â (pthread_mutex_setprioceiling): Likewise.
>>>>>>>> Â Â Â Â Â * nptl/pthread_mutex_timedlock.c (__pthread_mutex_timedlock):
>>>>>>>> Â Â Â Â Â Likewise.
>>>>>>>> Â Â Â Â Â * nptl/pthread_mutex_trylock.c (__pthread_mutex_trylock):
>>>>>>>> Â Â Â Â Â Likewise.
>>>>>>>> Â Â Â Â Â * nptl/pthread_mutex_unlock.c (__pthread_mutex_unlock_full):
>>>>>>>> Â Â Â Â Â Likewise.
>>>>>>>> Â Â Â Â Â * sysdeps/nptl/bits/thread-shared-types.h
>>>>>>>> Â Â Â Â Â (struct __pthread_mutex_s): Add comments.
>>>>>>>> Â Â Â Â Â * nptl/pthread_mutex_destroy.c (__pthread_mutex_destroy):
>>>>>>>> Â Â Â Â Â Use atomic_load_relaxed and atomic_store_relaxed.
>>>>>>>> Â Â Â Â Â * nptl/pthread_mutex_init.c (__pthread_mutex_init):
>>>>>>>> Â Â Â Â Â Use atomic_store_relaxed.
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
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