From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D4EEC4361B for ; Wed, 16 Dec 2020 18:19:12 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id CD39625CB2 for ; Wed, 16 Dec 2020 18:19:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CD39625CB2 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=tempfail smtp.mailfrom=dm-devel-bounces@redhat.com Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-541-aqogdIacM8uCdmpBeasAlg-1; Wed, 16 Dec 2020 13:19:07 -0500 X-MC-Unique: aqogdIacM8uCdmpBeasAlg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2A06B8144ED; Wed, 16 Dec 2020 18:18:59 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0B16F60C15; Wed, 16 Dec 2020 18:18:59 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id D02F750031; Wed, 16 Dec 2020 18:18:58 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id 0BGIId5s018077 for ; Wed, 16 Dec 2020 13:18:39 -0500 Received: by smtp.corp.redhat.com (Postfix) id 2EECA2166B2C; Wed, 16 Dec 2020 18:18:39 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast05.extmail.prod.ext.rdu2.redhat.com [10.11.55.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 2A1402166B27 for ; Wed, 16 Dec 2020 18:18:39 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 16CB9803CE8 for ; Wed, 16 Dec 2020 18:18:39 +0000 (UTC) Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-428-H6ICNcP9PJ6vdzhhMUENxA-1; Wed, 16 Dec 2020 13:18:34 -0500 X-MC-Unique: H6ICNcP9PJ6vdzhhMUENxA-1 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id E0A2FAF49; Wed, 16 Dec 2020 18:18:32 +0000 (UTC) From: mwilck@suse.com To: Christophe Varoqui , Benjamin Marzinski Date: Wed, 16 Dec 2020 19:16:57 +0100 Message-Id: <20201216181708.22224-19-mwilck@suse.com> In-Reply-To: <20201216181708.22224-1-mwilck@suse.com> References: <20201216181708.22224-1-mwilck@suse.com> MIME-Version: 1.0 X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-MIME-Autoconverted: from quoted-printable to 8bit by lists01.pubmisc.prod.ext.phx2.redhat.com id 0BGIId5s018077 X-loop: dm-devel@redhat.com Cc: lixiaokeng@huawei.com, dm-devel@redhat.com, Martin Wilck Subject: [dm-devel] [PATCH v3 18/29] libmultipath: fix log_thread startup and teardown X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit From: Martin Wilck This fixes several issues with the log_thread. First, the running flag logq_running should be set by the thread itself, not by log_thread_start()/_stop(). Second, the thread was both cancelled and terminated via a flag (again, logq_running). It's sufficient to just cancel and join it. Third, the locking wasn't cancel-safe in some places. Forth, log_thread_start() didn't wait for startup properly. Fifth, using (pthread_t)0 is wrong (pthread_t is opaque; there's no guarantee that 0 is not a valid pthread_t value). Sixth, pthread_cancel() was called under logq_lock, which doesn't make sense to me. Signed-off-by: Martin Wilck --- libmultipath/log_pthread.c | 62 +++++++++++++++++++++++++++----------- 1 file changed, 45 insertions(+), 17 deletions(-) diff --git a/libmultipath/log_pthread.c b/libmultipath/log_pthread.c index 0c327ff..3a2566a 100644 --- a/libmultipath/log_pthread.c +++ b/libmultipath/log_pthread.c @@ -13,6 +13,7 @@ #include "log_pthread.h" #include "log.h" #include "lock.h" +#include "util.h" static pthread_t log_thr; @@ -56,35 +57,52 @@ static void flush_logqueue (void) } while (empty == 0); } +static void cleanup_log_thread(__attribute((unused)) void *arg) +{ + logdbg(stderr, "log thread exiting"); + pthread_mutex_lock(&logev_lock); + logq_running = 0; + pthread_mutex_unlock(&logev_lock); +} + static void * log_thread (__attribute__((unused)) void * et) { int running; pthread_mutex_lock(&logev_lock); - logq_running = 1; + running = logq_running; + if (!running) + logq_running = 1; + pthread_cond_signal(&logev_cond); pthread_mutex_unlock(&logev_lock); + if (running) + /* already started */ + return NULL; + pthread_cleanup_push(cleanup_log_thread, NULL); mlockall(MCL_CURRENT | MCL_FUTURE); logdbg(stderr,"enter log_thread\n"); while (1) { pthread_mutex_lock(&logev_lock); - if (logq_running && !log_messages_pending) + pthread_cleanup_push(cleanup_mutex, &logev_lock); + while (!log_messages_pending) + /* this is a cancellation point */ pthread_cond_wait(&logev_cond, &logev_lock); log_messages_pending = 0; - running = logq_running; - pthread_mutex_unlock(&logev_lock); - if (!running) - break; + pthread_cleanup_pop(1); + flush_logqueue(); } + pthread_cleanup_pop(1); return NULL; } void log_thread_start (pthread_attr_t *attr) { - logdbg(stderr,"enter log_thread_start\n"); + int running = 0; + logdbg(stderr,"enter log_thread_start\n"); pthread_mutex_init(&logq_lock, NULL); pthread_mutex_init(&logev_lock, NULL); pthread_cond_init(&logev_cond, NULL); @@ -93,7 +111,15 @@ void log_thread_start (pthread_attr_t *attr) fprintf(stderr,"can't initialize log buffer\n"); exit(1); } - if (pthread_create(&log_thr, attr, log_thread, NULL)) { + + pthread_mutex_lock(&logev_lock); + pthread_cleanup_push(cleanup_mutex, &logev_lock); + if (!pthread_create(&log_thr, attr, log_thread, NULL)) + while (!(running = logq_running)) + pthread_cond_wait(&logev_cond, &logev_lock); + pthread_cleanup_pop(1); + + if (!running) { fprintf(stderr,"can't start log thread\n"); exit(1); } @@ -112,23 +138,25 @@ void log_thread_reset (void) void log_thread_stop (void) { + int running; + if (!la) return; logdbg(stderr,"enter log_thread_stop\n"); pthread_mutex_lock(&logev_lock); - logq_running = 0; - pthread_cond_signal(&logev_cond); - pthread_mutex_unlock(&logev_lock); - - pthread_mutex_lock(&logq_lock); - pthread_cancel(log_thr); - pthread_mutex_unlock(&logq_lock); - pthread_join(log_thr, NULL); - log_thr = (pthread_t)0; + pthread_cleanup_push(cleanup_mutex, &logev_lock); + running = logq_running; + if (running) { + pthread_cancel(log_thr); + pthread_cond_signal(&logev_cond); + } + pthread_cleanup_pop(1); flush_logqueue(); + if (running) + pthread_join(log_thr, NULL); pthread_mutex_destroy(&logq_lock); pthread_mutex_destroy(&logev_lock); -- 2.29.0 -- dm-devel mailing list dm-devel@redhat.com https://www.redhat.com/mailman/listinfo/dm-devel