From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751267Ab1H0Pc5 (ORCPT ); Sat, 27 Aug 2011 11:32:57 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:47584 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750882Ab1H0Pcz (ORCPT ); Sat, 27 Aug 2011 11:32:55 -0400 Date: Sat, 27 Aug 2011 17:32:51 +0200 From: Frederic Weisbecker To: Randy Dunlap Cc: LKML , Len Brown , "Paul E. McKenney" , Peter Zijlstra , Ingo Molnar Subject: Re: Bug: ACPI, scheduling while atomic (was Re: [PATCH 0/4] sched: Make sleep inside atomic detection work on !PREEMPT) Message-ID: <20110827153250.GO3298@somewhere> References: <1307555315-30989-1-git-send-email-fweisbec@gmail.com> <20110608224939.GC25771@somewhere.redhat.com> <20110824205745.cd3f5f6c.rdunlap@xenotime.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110824205745.cd3f5f6c.rdunlap@xenotime.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 24, 2011 at 08:57:45PM -0700, Randy Dunlap wrote: > On Thu, 9 Jun 2011 00:49:41 +0200 Frederic Weisbecker wrote: > > > On Wed, Jun 08, 2011 at 07:48:31PM +0200, Frederic Weisbecker wrote: > > > Aside it may mostly avoid the need for a specific PROVE_RCU > > > check when we sleep inside an rcu read side critical section. > > > > > > Better make sleeping inside atomic sections work everywhere. > > > > BTW, it has led to detect a bug in the ACPI code. It happens in > > !CONFIG_PREEMPT: > > > > [ 0.160187] BUG: scheduling while atomic: swapper/0/0x10000002 > > [ 0.166016] no locks held by swapper/0. > > [ 0.170014] Modules linked in: > > [ 0.173107] Pid: 0, comm: swapper Not tainted 2.6.39+ #124 > > [ 0.180014] Call Trace: > > [ 0.182481] [] __schedule_bug+0x85/0x90 > > [ 0.187967] [] schedule+0x75c/0xa40 > > [ 0.190022] [] ? trace_hardirqs_on+0xd/0x10 > > [ 0.200023] [] ? acpi_ps_free_op+0x22/0x24 > > [ 0.205776] [] __cond_resched+0x25/0x40 > > [ 0.210022] [] _cond_resched+0x2b/0x40 > > [ 0.215420] [] acpi_ps_complete_op+0x262/0x278 > > [ 0.220023] [] acpi_ps_parse_loop+0x80b/0x960 > > [ 0.230023] [] acpi_ps_parse_aml+0x98/0x274 > > [ 0.235859] [] acpi_ns_one_complete_parse+0x103/0x120 > > [ 0.240021] [] ? up+0x2a/0x50 > > [ 0.244641] [] acpi_ns_parse_table+0x1b/0x34 > > [ 0.250022] [] acpi_ns_load_table+0x4a/0x8c > > [ 0.260023] [] acpi_load_tables+0x9c/0x15d > > [ 0.265774] [] acpi_early_init+0x6c/0xf7 > > [ 0.270022] [] start_kernel+0x400/0x415 > > [ 0.275508] [] x86_64_start_reservations+0x131/0x135 > > [ 0.280022] [] x86_64_start_kernel+0x103/0x112 > > > > ACPI_PREEMPTION_POINT() is called from acpi_ps_complete_op() and schedules > > if !PREEMPT. But preemption is disabled as we are in early bootup. > > This still happens in 3.1-rc[123]. > Was there a patch for it? I think this patch should fix it, and may make it to mainline soon: http://git.kernel.org/?p=linux/kernel/git/paulmck/linux-2.6-rcu.git;a=commitdiff;h=61b12d4413c866abbf0d0cf18f5a2bd4420ca15e