From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757123AbYJGHJt (ORCPT ); Tue, 7 Oct 2008 03:09:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752054AbYJGHJk (ORCPT ); Tue, 7 Oct 2008 03:09:40 -0400 Received: from one.firstfloor.org ([213.235.205.2]:42051 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751728AbYJGHJk (ORCPT ); Tue, 7 Oct 2008 03:09:40 -0400 Date: Tue, 7 Oct 2008 09:15:44 +0200 From: Andi Kleen To: "Paul E. McKenney" Cc: Andi Kleen , mingo@elte.hu, linux-kernel@vger.kernel.org, rjw@sisk.pl, dipankar@in.ibm.com, tglx@linuxtronix.de Subject: Re: RCU hang on cpu re-hotplug with 2.6.27rc8 Message-ID: <20081007071544.GC20740@one.firstfloor.org> References: <20081006141220.GA14160@basil.nowhere.org> <20081006232837.GA1157@basil.nowhere.org> <20081007030822.GC6820@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20081007030822.GC6820@linux.vnet.ibm.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Could you please try the patch at the following URL (from Thomas > Gleixner)? > > http://www.rdrop.com/users/paulmck/patches/2.6.27-rc7-tglx-timer-1.patch > > This fixed some CPU hotplug hangs that I was seeing in 2.6.27-rc7 and > -rc8. Alternatively, try 2.6.27-rc9, which seems to include Thomas's > patch. Still happens with rc9. This time with frame pointers: bash D 00000000ffff975e 0 4770 4757 ffff8804bcda3bf8 0000000000000082 ffff8804bcda3c18 0000000000000296 ffff8804bde4e6b0 ffff8804be6fc630 ffff8804bde4e8f8 0000000e00000296 ffff8804bcda3c18 ffffffff808cfd98 ffff880288064780 ffff88027d18ec98 Call Trace: [] schedule_timeout+0x22/0xb4 [] ? __switch_to+0x320/0x330 [] ? cpupri_set+0xc5/0xd8 [] wait_for_common+0xcd/0x131 [] ? default_wake_function+0x0/0xf [] wait_for_completion+0x18/0x1a [] synchronize_rcu+0x35/0x3c [] ? wakeme_after_rcu+0x0/0x12 [] partition_sched_domains+0x9b/0x1dd [] ? wake_up_process+0x10/0x12 [] update_sched_domains+0x2e/0x35 [] notifier_call_chain+0x33/0x5b [] __raw_notifier_call_chain+0x9/0xb [] raw_notifier_call_chain+0xf/0x11 [] _cpu_up+0xd3/0x10c [] cpu_up+0x57/0x67 [] store_online+0x4d/0x75 [] sysdev_store+0x1b/0x1d [] sysfs_write_file+0xe0/0x11c [] vfs_write+0xae/0x137 [] sys_write+0x47/0x6f [] system_call_fastpath+0x16/0x1b BTW it also happens reliably every time. Reproduced it three times now. I just do laut:~ # echo 0 > /sys/devices/system/cpu/cpu15/online laut:~ # echo 0 > /sys/devices/system/cpu/cpu14/online laut:~ # echo 1 > /sys/devices/system/cpu/cpu14/online laut:~ # echo 1 > /sys/devices/system/cpu/cpu15/online -Andi