From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 90065 invoked by alias); 16 Jul 2018 11:57:04 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 90041 invoked by uid 89); 16 Jul 2018 11:57:03 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-3.3 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=leads, race, somebody X-HELO: mx0a-001b2d01.pphosted.com Subject: Re: [PING][PATCH] Fix race in pthread_mutex_lock while promoting to PTHREAD_MUTEX_ELISION_NP [BZ #23275] To: libc-alpha@sourceware.org References: <4614fea8-43b9-0125-1346-603ad8ad66e4@linux.ibm.com> <8e0d0ec6-5071-1d15-1f40-20a4928871a0@linux.ibm.com> From: Stefan Liebler Date: Mon, 16 Jul 2018 11:57:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <8e0d0ec6-5071-1d15-1f40-20a4928871a0@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit x-cbid: 18071611-0028-0000-0000-000002DC1ABA X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18071611-0029-0000-0000-00002393D7B6 Message-Id: X-SW-Source: 2018-07/txt/msg00424.txt.bz2 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: >>>>> >>>>>      [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. >>>> >>> >> >