From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751691AbWGZPB2 (ORCPT ); Wed, 26 Jul 2006 11:01:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751692AbWGZPB2 (ORCPT ); Wed, 26 Jul 2006 11:01:28 -0400 Received: from nf-out-0910.google.com ([64.233.182.189]:42428 "EHLO nf-out-0910.google.com") by vger.kernel.org with ESMTP id S1751688AbWGZPB1 (ORCPT ); Wed, 26 Jul 2006 11:01:27 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=fJXaeb5P8FohruTNhtMAsNW5RJNVq8BngbGfUQ5gr+dA1P68j/UYOAMIFivUc0hM85txXSEy93ZmAyjUDldZCAXFV2FK0KFW4R/xd/jFxr11eoySPza/64cNhOLaQW0I+PBfKvwGMcsOLzdV+kXmIzcI5Rai8d/LqgAxGwa4fkk= Message-ID: <6bffcb0e0607260801s73cdee9avd207984712011c80@mail.gmail.com> Date: Wed, 26 Jul 2006 17:01:26 +0200 From: "Michal Piotrowski" To: torvalds@osdl.org Subject: Re: [2.6.18-rc2-gabb5a5cc BUG] Lukewarm IQ detected in hotplug locking Cc: linux-kernel@vger.kernel.org In-Reply-To: <6bffcb0e0607260151i6065457g6acf9f4d9b2a6d50@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <6bffcb0e0607251657w47697883n74bab2255fd44ece@mail.gmail.com> <20060725181415.483838f5.pj@sgi.com> <6bffcb0e0607260151i6065457g6acf9f4d9b2a6d50@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 26/07/06, Michal Piotrowski wrote: > Here is the bad commit > > aa95387774039096c11803c04011f1aa42d85758 is first bad commit > commit aa95387774039096c11803c04011f1aa42d85758 > Author: Linus Torvalds > Date: Sun Jul 23 12:12:16 2006 -0700 > > cpu hotplug: simplify and hopefully fix locking > > The CPU hotplug locking was quite messy, with a recursive lock to > handle the fact that both the actual up/down sequence wanted to > protect itself from being re-entered, but the callbacks that it > called also tended to want to protect themselves from CPU events. > > This splits the lock into two (one to serialize the whole hotplug > sequence, the other to protect against the CPU present bitmaps > changing). The latter still allows recursive usage because some > subsystems (ondemand policy for cpufreq at least) had already gotten > too used to the lax locking, but the locking mistakes are hopefully > now less fundamental, and we now warn about recursive lock usage > when we see it, in the hope that it can be fixed. > > Signed-off-by: Linus Torvalds > > :040000 040000 9189d56fe28f6823287e9d1e79976e68074da5db > 266b4ea87d2ac441bc02ad2c > 4ba2c4f332c7c0ce M include > :040000 040000 3dfe69afef86aef8e6472d6d543ba965833e201b > bfb64b2824c1e23f0629e976 > 2526fd11b789d51e M kernel Sorry for the noise. The bug is fixed in latest git tree. Regards, Michal -- Michal K. K. Piotrowski LTG - Linux Testers Group (http://www.stardust.webpages.pl/ltg/wiki/)