From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 116579 invoked by alias); 23 Jul 2018 06:42:52 -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 116440 invoked by uid 89); 23 Jul 2018 06:42:51 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-3.1 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=somebody, ensuring 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> Cc: "Carlos O'Donell" , Torvald Riegel From: Stefan Liebler Date: Mon, 23 Jul 2018 06:42:00 -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: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit x-cbid: 18072306-0020-0000-0000-000002A9C694 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18072306-0021-0000-0000-000020F64EDA Message-Id: <79443e7f-ed44-4602-4555-dc179657ee9b@linux.ibm.com> X-SW-Source: 2018-07/txt/msg00682.txt.bz2 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: >>>>>> >>>>>>      [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. >>>>> >>>> >>> >> >