From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15190 invoked by alias); 6 Aug 2012 17:18:44 -0000 Received: (qmail 15175 invoked by uid 22791); 6 Aug 2012 17:18:43 -0000 X-SWARE-Spam-Status: No, hits=-4.3 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00,KHOP_THREADED X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 06 Aug 2012 17:18:29 +0000 From: "architectbum at hotmail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/54185] condition_variable not properly destructed Date: Mon, 06 Aug 2012 17:18:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: libstdc++ X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: architectbum at hotmail dot com X-Bugzilla-Status: ASSIGNED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: redi at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2012-08/txt/msg00352.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54185 --- Comment #6 from architectbum at hotmail dot com 2012-08-06 17:18:26 UTC --- I don't have this_thread::sleep_for in my build, but presumably it wouldn't help as the segfault comes inside the pthread_cond_wait function. The testcase as written already ensures that NUM_THREADS-1 threads are actually waiting at cond->wait when notify_all is called (thanks to the lock); the problem seems to be a race between the final thread doing 'delete cc' and the other threads clearing the part of pthread_cond_wait which assumes the condition variable's address still points to a valid object. To be clear, this isn't a bug with pthread, just the way which libstdc++ uses it. If/when ~condition_variable (via delete) calls gthread_cond_destroy, libpthread properly avoids the race.