From owner-cvs-all@FreeBSD.ORG Tue Jun 5 15:43:05 2007 Return-Path: X-Original-To: cvs-all@freebsd.org Delivered-To: cvs-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 401C516A400 for ; Tue, 5 Jun 2007 15:43:05 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: from ug-out-1314.google.com (ug-out-1314.google.com [66.249.92.172]) by mx1.freebsd.org (Postfix) with ESMTP id 950CA13C45E for ; Tue, 5 Jun 2007 15:43:04 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: by ug-out-1314.google.com with SMTP id u2so230177uge for ; Tue, 05 Jun 2007 08:43:03 -0700 (PDT) DKIM-Signature: a=rsa-sha1; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=ELfvLgrm2038tW04I8uQknBcqQ4VDSv/+dBRVLb6j6UfxmUHCvomKH8XoXu76GchC9/TPc0mIVLZf2rZoVZtAC+fbNyv3buGs7HEeZ91ePThg9IPOJDdB29Nlg+lMV9/wecVuLySGlVPNWxaXjoZTIHm/1ITmmv0iLuPUEDcyWo= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=L908KgbGT8ubtZZkASua4g6kbyO5aFsiSJihoYhDPNfiFDYT51xUHSW+EANrMVSGvYxZKHK6tQjaG7/jJ65AylpmHtKTZOSCpothONob9yjui5j0gZfYXNmsZUKLqKJlgZoM308vr1nOz6Jxn8OGNs3TkNjyze2YU7Gd2N8raVU= Received: by 10.78.181.13 with SMTP id d13mr2538105huf.1181058183455; Tue, 05 Jun 2007 08:43:03 -0700 (PDT) Received: by 10.78.120.9 with HTTP; Tue, 5 Jun 2007 08:43:03 -0700 (PDT) Message-ID: <3bbf2fe10706050843x5aaafaafy284e339791bcfe42@mail.gmail.com> Date: Tue, 5 Jun 2007 17:43:03 +0200 From: "Attilio Rao" Sender: asmrookie@gmail.com To: "Bruce Evans" In-Reply-To: <3bbf2fe10706050829o2d756a4cu22f98cf11c01f5e4@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <200706051420.l55EKEih018925@repoman.freebsd.org> <20070606003412.W35544@besplex.bde.org> <20070605150005.GW2268@deviant.kiev.zoral.com.ua> <20070605150521.GX2268@deviant.kiev.zoral.com.ua> <20070606011022.R35623@besplex.bde.org> <3bbf2fe10706050829o2d756a4cu22f98cf11c01f5e4@mail.gmail.com> X-Google-Sender-Auth: 0d4b8be6a9c1c468 Cc: Kostik Belousov , cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/kern kern_mutex.c X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Jun 2007 15:43:05 -0000 2007/6/5, Attilio Rao : > 2007/6/5, Bruce Evans : > > > > I get a "spin lock held too long" panic during (an interrupt in?) acpi > > initialization on booting non-PREEMPTION SCHED_4BSD SMP. Haven't tried > > other cases. > > Do you have a backtrace or any other debugging stuffs available? Mmm, I think I got the bug. basically, in kern_mutex.c::_mtx_unlock_sleep(), in the not-preemptive case what happens at some point is: td = curthread; if (td->td_critnest > 0 || td1->td_priority >= td->td_priority) return; thread_lock(td1); if (!TD_IS_RUNNING(td1)) { ... mi_switch(SW_INVOL, NULL); ... } thread_unlock(td1); Which is wrong beacause td1 is not curthread and really curthread should be locked too when context switching. To a first look the idea is that td and td1 should be locked both, but I just want more time to look better at it. Attilio -- Peace can only be achieved by understanding - A. Einstein