From owner-freebsd-threads@FreeBSD.ORG Thu Jul 16 12:26:50 2009 Return-Path: Delivered-To: freebsd-threads@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B3DD51065678 for ; Thu, 16 Jul 2009 12:26:50 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: from mail-bw0-f208.google.com (mail-bw0-f208.google.com [209.85.218.208]) by mx1.freebsd.org (Postfix) with ESMTP id 3AD968FC19 for ; Thu, 16 Jul 2009 12:26:50 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: by bwz4 with SMTP id 4so67940bwz.43 for ; Thu, 16 Jul 2009 05:26:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:date:x-google-sender-auth:message-id:subject:from:to:cc :content-type:content-transfer-encoding; bh=NPkQaOCM6nbQyXaALr2+gBr1uypJCBa02tOcN8hiPGk=; b=HPuYYBL9QwQSZiDO5xYDmObARbgIJ/JBhXRLOyCYyBjw1iW5QqBzRvHHg7qilwpwHv Sdu9X8Lfi8+M7i+kJTf/nGVVL4BvxyFchSojDe52CTRs1lTGAkvIt4LzlDU9V9wONoY5 p47KAHs5PtlNro07bp3hEO9F4t5iyvbb14iQY= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=RiCzQnwETTGHyMAaZ8UKaE/BNMG2/eH92ZDwEHulimrby2hgU1oR+L7yUjl/jKo4TO UCKj5o4Ne9ENGRW6uz+xQ9TVyQc2YDcr+CvxkCs5hGHsudg0l8EDPQ9uBICumBiSePmh j59xBbuQtddyYdY/jDKKhIMFLCYhs7U8R2DLU= MIME-Version: 1.0 Sender: asmrookie@gmail.com Received: by 10.223.114.74 with SMTP id d10mr4393861faq.87.1247747209207; Thu, 16 Jul 2009 05:26:49 -0700 (PDT) In-Reply-To: <200907152140.n6FLe42l045879@freefall.freebsd.org> References: <200907152140.n6FLe42l045879@freefall.freebsd.org> Date: Thu, 16 Jul 2009 14:26:49 +0200 X-Google-Sender-Auth: b03de7c3679a91c1 Message-ID: <3bbf2fe10907160526l2f066698qce8a5e77aee6366b@mail.gmail.com> From: Attilio Rao To: Nick Esborn Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: freebsd-threads@freebsd.org Subject: Re: threads/136345: Recursive read rwlocks in thread A cause deadlock with write lock in thread B X-BeenThere: freebsd-threads@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Threading on FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Jul 2009 12:26:51 -0000 2009/7/15 Nick Esborn : > The following reply was made to PR threads/136345; it has been noted by GNATS. > > From: Nick Esborn > To: bug-followup@FreeBSD.org, > rink@FreeBSD.org > Cc: > Subject: Re: threads/136345: Recursive read rwlocks in thread A cause deadlock with write lock in thread B > Date: Wed, 15 Jul 2009 14:32:38 -0700 > > This is an OpenPGP/MIME signed message (RFC 2440 and 3156) > --Apple-Mail-19-950902279 > Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes > Content-Transfer-Encoding: 7bit > > Even after the above patch, I still run into occasional MySQL thread > deadlocks, which I originally described in what is now threads/135673. > > I also posted on freebsd-current a few days ago: > > http://lists.freebsd.org/pipermail/freebsd-current/2009-July/009328.html > > I'd be happy to collect whatever data would be helpful in tracking > down this deadlock. This only seems to happen under our production > workload, so that might make it harder to capture meaningful debug > data, but I'm certainly willing to try. I can also arrange for > developer access to the system in question, if that would help > significantly. So did you backport this to 7 and still experience deadlocks? I just committed the fix to HEAD not to STABLE branch. Thanks, Attilio -- Peace can only be achieved by understanding - A. Einstein