Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756036Ab2HTJ1u (ORCPT ); Mon, 20 Aug 2012 05:27:50 -0400 Received: from mga11.intel.com ([192.55.52.93]:24453 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753977Ab2HTJ1s (ORCPT ); Mon, 20 Aug 2012 05:27:48 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.77,796,1336374000"; d="scan'208";a="206249454" Date: Mon, 20 Aug 2012 17:27:44 +0800 From: Fengguang Wu To: Michael Wang Cc: Thomas Gleixner , Yinghai Lu , Suresh Siddha , LKML Subject: Re: BUG: scheduling while atomic, under native_smp_prepare_cpus() Message-ID: <20120820092744.GA3668@localhost> References: <20120817134944.GA539@localhost> <50320163.5080703@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50320163.5080703@linux.vnet.ibm.com> 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 Content-Length: 5159 Lines: 106 Hi Michael, On Mon, Aug 20, 2012 at 05:20:35PM +0800, Michael Wang wrote: > On 08/17/2012 09:49 PM, Fengguang Wu wrote: > > Hi, FengGuang > > native_smp_prepare_cpus has already disabled the preempt before > reach __irq_alloc_descs(), and sleep in mutex_lock() cause the bug. > > May be the follow patch could help to solve the issue(actually I > think the true problem should be in _cond_resched...). Is this a debug patch? Since what it does is to conditionally disable the warning. > I can't do test by my self since I can't reproduce the issue on my > machine, the kernel_init thread never got a need sched flag set at > that moment in my case... I'll try it and report back :) Thanks, Fengguang > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 4376c9f..3396c33 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -3321,7 +3321,8 @@ static inline void schedule_debug(struct task_struct *prev) > * schedule() atomically, we ignore that path for now. > * Otherwise, whine if we are scheduling when we should not be. > */ > - if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) > + if (unlikely(in_atomic_preempt_off() && !prev->exit_state > + && system_state == SYSTEM_RUNNING)) > __schedule_bug(prev); > rcu_sleep_check(); > > > > Trace one (full config/dmesg attached): > > > > [ 0.042794] init IO_APIC IRQs [ 0.043305] apic 2 pin 0 not > > connected [ 0.043953] BUG: scheduling while atomic: > > swapper/0/1/0x10000002 [ 0.044017] no locks held by swapper/0/1. [ > > 0.044692] Pid: 1, comm: swapper/0 Not tainted > > 3.6.0-rc1-00420-gb7aebb9 #34 [ 0.045861] Call Trace: [ 0.048071] > > [] __schedule_bug+0x5e/0x70 [ 0.048890] [] > > __schedule+0x91/0xb10 [ 0.049660] [] ? > > vsnprintf+0x33a/0x450 [ 0.050444] [] ? > > lg_local_lock+0x6/0x70 [ 0.051256] [] ? > > wait_for_xmitr+0x31/0x90 [ 0.052019] [] ? > > do_raw_spin_unlock+0xa5/0xf0 [ 0.052903] [] ? > > _raw_spin_unlock+0x22/0x30 [ 0.053759] [] ? > > up+0x1b/0x70 [ 0.054421] [] __cond_resched+0x1b/0x30 [ > > 0.055228] [] _cond_resched+0x45/0x50 [ 0.056020] > > [] mutex_lock_nested+0x28/0x370 [ 0.056884] > > [] ? console_unlock+0x3a2/0x4e0 [ 0.057741] > > [] __irq_alloc_descs+0x39/0x1c0 [ 0.058589] > > [] io_apic_setup_irq_pin+0x2c/0x310 [ 0.060042] > > [] setup_IO_APIC+0x101/0x744 [ 0.060878] [] ? > > clear_IO_APIC+0x31/0x50 [ 0.061695] [] > > native_smp_prepare_cpus+0x538/0x680 [ 0.062644] [] ? > > do_one_initcall+0x12c/0x12c [ 0.063517] [] ? > > do_one_initcall+0x12c/0x12c [ 0.064016] [] > > kernel_init+0x4b/0x17f [ 0.064790] [] ? > > do_one_initcall+0x12c/0x12c [ 0.065660] [] > > kernel_thread_helper+0x6/0x10 [ 0.066592] IOAPIC[0]: Set routing > > entry (2-1 -> 0x41 -> IRQ 1 Mode:0 Active:0 Dest:1) [ 0.068045] > > IOAPIC[0]: Set routing entry (2-2 -> 0x51 -> IRQ 0 Mode:0 Active:0 > > Dest:1) > > > > Trace two (triggered by another config): > > > > [ 0.288018] tlb_flushall_shift is 0xffffffff [ 0.316019] > > Freeing SMP alternatives: 20k freed [ 0.364022] BUG: scheduling > > while atomic: swapper/0/1/0x10000002 [ 0.364022] no locks held by > > swapper/0/1. [ 0.368023] Pid: 1, comm: swapper/0 Not tainted > > 3.6.0-rc1 #1 [ 0.368023] Call Trace: [ 0.368023] [<79812e23>] > > __schedule_bug+0x41/0x53 [ 0.372023] [<79820393>] > > __schedule+0x62/0x488 [ 0.376023] [<792d17ae>] ? > > radix_tree_lookup+0xa/0xc [ 0.376023] [<79071f4e>] ? > > rcu_irq_exit+0x61/0x66 [ 0.376023] [<79026be7>] ? > > irq_exit+0x60/0x6c [ 0.376023] [<790035df>] ? do_IRQ+0x6c/0x80 [ > > 0.380023] [<7903d794>] __cond_resched+0x16/0x26 [ 0.380023] > > [<79820888>] _cond_resched+0x13/0x1c [ 0.380023] [<7909f30a>] > > slab_pre_alloc_hook.isra.44+0x2e/0x33 [ 0.380023] [<790a09c6>] > > kmem_cache_alloc+0x1b/0xbb [ 0.384024] [<792ce416>] ? > > alloc_cpumask_var_node+0x1a/0x72 [ 0.384024] [<792ce416>] > > alloc_cpumask_var_node+0x1a/0x72 [ 0.384024] [<792ce486>] > > alloc_cpumask_var+0xb/0xd [ 0.388024] [<792ce493>] > > zalloc_cpumask_var+0xb/0xd [ 0.388024] [<79bfe1fd>] > > native_smp_prepare_cpus+0x93/0x380 [ 0.388024] [<79bf6a7e>] ? > > do_one_initcall+0x10c/0x10c [ 0.388024] [<79bf6ac6>] > > kernel_init+0x48/0x16e [ 0.392024] [<79bf6a7e>] ? > > do_one_initcall+0x10c/0x10c [ 0.392024] [<7982241e>] > > kernel_thread_helper+0x6/0xd [ 0.400025] smpboot: SMP disabled [ > > 0.400025] Performance Events: > > > > Thanks, Fengguang > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/