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

[Stefan Liebler]

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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