From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751212AbXCWBrn (ORCPT ); Thu, 22 Mar 2007 21:47:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752844AbXCWBrn (ORCPT ); Thu, 22 Mar 2007 21:47:43 -0400 Received: from smtp.osdl.org ([65.172.181.24]:32850 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751212AbXCWBrm (ORCPT ); Thu, 22 Mar 2007 21:47:42 -0400 Date: Thu, 22 Mar 2007 18:40:41 -0700 (PDT) From: Linus Torvalds To: Ingo Molnar , "Eric W. Biederman" , Thomas Gleixner cc: Nick Piggin , Mingming Cao , Adrian Bunk , Andrew Morton , Linux Kernel Mailing List , Michal Piotrowski , Mariusz Kozlowski , Oliver Pinter , Sid Boyce , Nick Piggin , Jens Axboe Subject: Re: [1/6] 2.6.21-rc4: known regressions In-Reply-To: <1174612132.16068.114.camel@localhost.localdomain> Message-ID: References: <20070318184908.GU752@stusta.de> <46020385.50301@yahoo.com.au> <1174612132.16068.114.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org [ Ok, I think it's those timers again... Ingo: let me just state how *happy* I am that I told you off when you wanted to merge the hires timers and NO_HZ before 2.6.20 because they were "stable". You were wrong, and 2.6.20 is at least in reasonable shape. Now we just need to make sure that 2.6.21 will be too.. ] On Thu, 22 Mar 2007, Mingming Cao wrote: > > I might missed something, so far I can't see a deadlock yet. > If there is a deadlock, I think we should see ext3_xattr_release_block() > and ext3_forget() on the stack. Is this the case? No. What's strange is that two (maybe more, I didn't check) processes seem to be stuck in [] schedule_timeout+0x70/0x8e [] schedule_timeout_uninterruptible+0x15/0x17 [] journal_stop+0xe2/0x1e6 [] journal_force_commit+0x1d/0x1f [] ext3_force_commit+0x22/0x24 [] ext3_write_inode+0x34/0x3a [] __writeback_single_inode+0x1c5/0x2cb [] sync_inode+0x1c/0x2e [] ext3_sync_file+0xab/0xc0 [] do_fsync+0x4b/0x98 [] __do_fsync+0x20/0x2f [] sys_fsync+0xd/0xf [] syscall_call+0x7/0xb but that that thing is literally: ... do { old_handle_count = transaction->t_handle_count; schedule_timeout_uninterruptible(1); } while (old_handle_count != transaction->t_handle_count); ... and especially if nothing is happening, I'd not expect "transaction->t_handle_count" to keep changing, so it should stop very quickly. Maybe it's CONFIG_NO_HZ again, and the problem is that timeout, and simply no timer tick happening? Bingo. I think that's it. active timers: #0: hardirq_stack, tick_sched_timer, S:01 # expires at 9530893000000 nsecs [in -2567889 nsecs] #1: hardirq_stack, hrtimer_wakeup, S:01 # expires at 10858649798503 nsecs [in 1327754230614 nsecs] .expires_next : 9530893000000 nsecs See http://lkml.org/lkml/2007/3/16/288 and that in turn points to the kernel log: http://www.stardust.webpages.pl/files/tbf/bitis-gabonica/2.6.21-rc4/git-console.log