From owner-freebsd-stable@FreeBSD.ORG Sat Jun 6 16:24:46 2015 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 5B78B994 for ; Sat, 6 Jun 2015 16:24:46 +0000 (UTC) (envelope-from gpalmer@freebsd.org) Received: from mail.in-addr.com (mail.in-addr.com [IPv6:2a01:4f8:191:61e8::2525:2525]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 1CC3E15C1 for ; Sat, 6 Jun 2015 16:24:46 +0000 (UTC) (envelope-from gpalmer@freebsd.org) Received: from gjp by mail.in-addr.com with local (Exim 4.85 (FreeBSD)) (envelope-from ) id 1Z1Gtn-000OU6-Ld; Sat, 06 Jun 2015 17:24:43 +0100 Date: Sat, 6 Jun 2015 17:24:43 +0100 From: Gary Palmer To: Konstantin Belousov Cc: Andre Meiser , freebsd-stable@freebsd.org Subject: Re: Many core dumps in pthread_getspecific. Message-ID: <20150606162443.GA29089@in-addr.com> References: <20150603145838.GX2499@kib.kiev.ua> <20150606150821.GG2499@kib.kiev.ua> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150606150821.GG2499@kib.kiev.ua> X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: gpalmer@freebsd.org X-SA-Exim-Scanned: No (on mail.in-addr.com); SAEximRunCond expanded to false X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 06 Jun 2015 16:24:46 -0000 On Sat, Jun 06, 2015 at 06:08:21PM +0300, Konstantin Belousov wrote: > On Sat, Jun 06, 2015 at 09:50:22AM +0200, Andre Meiser wrote: > > On Wed, Jun 03, 2015 at 16:58 +0200, Konstantin Belousov wrote: > > > You should recompile both libc and libthr with debugging symbols, like > > > cd /usr/src > > > (cd lib/libc && make all install DEBUG_FLAGS=-g) > > > (cd lib/libthr && make all install DEBUG_FLAGS=-g) > > > then obtain the core dump and post backtraces. > > > > Thank you, that was exactly what I was looking for. Now I like FreeBSD > > even more. ;) > > > > I made this short after and also rebooted the entire system to make > > all programmes use those debug libs. Since than I had not a single > > core dump. > Which means, most likely, that your installation was corrupted. > > > > > I experienced something similar in the past, that with activated > > debugging some errors can't be triggered any longer. > > > > At the moment I'm happy without crashes and I can work with this > > system. As soon as I'm getting a new core dump, I'll post the > > backtrace. If this won't happen for weeks, I may recompile the libs > > again, try to find a way to trigger the bug on purpose, enable the > > debug flag again and than provide the info. > > > > In the meantime, maybe a core developer may think about the lines > > of code I'd provided. Why is _get_curthread() compared to NULL at > > thr_kern.c (line 601) but not at thr_spec.c (line 224)? Either > > _get_curthread() never ever returns NULL, than it's pointless to test > > it or it's missing [not only] at thr_spec.c. > Whole thr_kern.c file is 213 lines long in the HEAD. > Might be, a core developer has a 601-lines long thr_kern.c. lib/libkse/thread/thr_kern.c is longer and has a _get_curthread() call around line 601. Regards, Gary > The only way for _get_curthread() to return NULL or, more likely, a > garbage, is for the call to _get_curthread() to happens before the > threading machinery was initialized. WRT the thr_spec.c, correct code > must call pthread_key_create(3) at least once before calling any other > pthread_key_*(3) functions. The implementation of pthread_key_create(3) > interface, the function _pthread_key_create(), calls _thr_check_init() > as the first action, and this helper initializes threading. So if > _get_curthread() in any pthread_key_*() function returns NULL or > garbage, this is an application' bug.