From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 122032 invoked by alias); 3 Jul 2018 06:28:26 -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 118331 invoked by uid 89); 3 Jul 2018 06:28:17 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-2.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=Bye, HContent-Transfer-Encoding:8bit 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> From: Stefan Liebler Date: Tue, 03 Jul 2018 06:28:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit x-cbid: 18070306-0008-0000-0000-0000024F0DB6 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18070306-0009-0000-0000-000021B51A30 Message-Id: X-SW-Source: 2018-07/txt/msg00046.txt.bz2 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. >> >