From owner-freebsd-hackers@freebsd.org Mon Nov 21 15:10:48 2016 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 57C47C4D263 for ; Mon, 21 Nov 2016 15:10:48 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from kib.kiev.ua (kib.kiev.ua [IPv6:2001:470:d5e7:1::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id F2328F90 for ; Mon, 21 Nov 2016 15:10:47 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from tom.home (kib@localhost [127.0.0.1]) by kib.kiev.ua (8.15.2/8.15.2) with ESMTPS id uALFAfTA082317 (version=TLSv1 cipher=DHE-RSA-CAMELLIA256-SHA bits=256 verify=NO); Mon, 21 Nov 2016 17:10:41 +0200 (EET) (envelope-from kostikbel@gmail.com) DKIM-Filter: OpenDKIM Filter v2.10.3 kib.kiev.ua uALFAfTA082317 Received: (from kostik@localhost) by tom.home (8.15.2/8.15.2/Submit) id uALFAff6082316; Mon, 21 Nov 2016 17:10:41 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: tom.home: kostik set sender to kostikbel@gmail.com using -f Date: Mon, 21 Nov 2016 17:10:40 +0200 From: Konstantin Belousov To: Volker Lendecke Cc: freebsd-hackers@freebsd.org Subject: Re: process shared mutexes? Message-ID: <20161121151040.GA54029@kib.kiev.ua> References: <20161121133528.GA30947@sernet.de> <20161121135036.GY54029@kib.kiev.ua> <20161121141616.GB30947@sernet.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161121141616.GB30947@sernet.de> User-Agent: Mutt/1.7.1 (2016-10-04) X-Spam-Status: No, score=-2.0 required=5.0 tests=ALL_TRUSTED,BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FROM,NML_ADSP_CUSTOM_MED autolearn=no autolearn_force=no version=3.4.1 X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on tom.home X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 21 Nov 2016 15:10:48 -0000 On Mon, Nov 21, 2016 at 03:16:16PM +0100, Volker Lendecke wrote: > On Mon, Nov 21, 2016 at 03:50:36PM +0200, Konstantin Belousov wrote: > > On Mon, Nov 21, 2016 at 02:35:28PM +0100, Volker Lendecke wrote: > > > Hello! > > > > > > For Samba's tdb I'm trying to get process shared robust mutexes to > > > work. However, tdb has a usage pattern that seems to confuse FreeBSD > > > 11 (32-bit x86 if that matters). > > > > > > The attached program fails in the final pthread_mutex_lock call. If I > > > comment out the call to > > > > > > ptr = mmap(NULL, 0xb0, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0x1000); > > > > > > it works. > > > > > > FWIW, tdb uses robust shared mutexes on Linux successfully for a while > > > now. I haven't tried Solaris yet, the only other platform I know about > > > that has them. > > > > > > What am I doing wrong? Please see the libthr(3) man page, in particular, read the RUN-TIME SETTINGS section, the description of the kern.ipc.umtx_vnode_persistent sysctl. Does setting the sysctl to 1 allow your program to run ? > > > > > > Thanks, > > > > > > > There is no attached program, please mail it either inline or put it > > somewhere on web. > > Hmm. Inline now. > > Volker > > > #include > #include > #include > #include > #include > #include > #include > #include > #include > > int main(int argc, const char *argv[]) > { > int fd, ret; > void *ptr; > pthread_mutex_t *m; > pthread_mutexattr_t attr; > > if (argc != 2) { > fprintf(stderr, "usage: %s \n", argv[0]); > return 1; > } > > fd = open(argv[1], O_RDWR|O_CREAT, 0644); > if (fd == -1) { > perror("open failed"); > return 1; > } > > ret = ftruncate(fd, 0x1000+0xb0); > if (ret == -1) { > perror("ftruncate failed"); > return 1; > } > > m = mmap(NULL, 0x1000, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); > if (m == MAP_FAILED) { > perror("mmap failed"); > return 1; > } > > ret = pthread_mutexattr_init(&attr); > if (ret != 0) { > fprintf(stderr, "pthread_mutexattr_init failed: %s\n", > strerror(ret)); > return 1; > } > > ret = pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED); > if (ret != 0) { > fprintf(stderr, "pthread_mutexattr_setpshared failed: %s\n", > strerror(ret)); > return 1; > } > > ret = pthread_mutex_init(m, &attr); > if (ret != 0) { > fprintf(stderr, "pthread_mutex_init failed: %s\n", > strerror(ret)); > return 1; > } > > ret = munmap(m, 0x1000); > if (ret == -1) { > perror("munmap failed"); > return 1; > } > > #if 1 > ptr = mmap(NULL, 0xb0, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0x1000); > if (ptr == MAP_FAILED) { > perror("mmap failed"); > return 1; > } > #endif > > m = mmap(NULL, 0x1000, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); > if (m == MAP_FAILED) { > perror("mmap failed"); > return 1; > } > > ret = pthread_mutex_lock(m); > if (ret != 0) { > fprintf(stderr, "pthread_mutex_lock failed: %s\n", > strerror(ret)); > return 1; > } > > ret = pthread_mutex_unlock(m); > if (ret != 0) { > fprintf(stderr, "pthread_mutex_lock failed: %s\n", > strerror(ret)); > return 1; > } > > return 0; > }