From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933602AbXGWDOQ (ORCPT ); Sun, 22 Jul 2007 23:14:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760281AbXGWDOE (ORCPT ); Sun, 22 Jul 2007 23:14:04 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.144]:43020 "EHLO e4.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750853AbXGWDOB (ORCPT ); Sun, 22 Jul 2007 23:14:01 -0400 Date: Sun, 22 Jul 2007 20:13:59 -0700 From: "Paul E. McKenney" To: Daniel Walker Cc: mingo@elte.hu, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Subject: Re: [PATCH -rt] drop spurious rcu unlock Message-ID: <20070723031359.GA25590@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <1185124958.2573.13.camel@imap.mvista.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1185124958.2573.13.camel@imap.mvista.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jul 22, 2007 at 10:22:37AM -0700, Daniel Walker wrote: > > Strange rcu_read_unlock() which causes a imbalance, and boot hang.. I > didn't notice a reason for it, and removing it allows my system to make > progress. > > This should go into the preempt-realtime-sched.patch Strange. I have been getting boots, kernbench runs, and rcutorture tests despite its being present. Though perhaps it was the cause of the (non-fatal) "scheduling while atomic" I got during a kernbench run -- I was assuming it was my fault somehow. Non-reproducible. :-/ Thanx, Paul BUG: sleeping function called from invalid context cc1(29651) at kernel/rtmutex.c:636 in_atomic():1 [00000001], irqs_disabled():0 [] __might_sleep+0xf3/0xf9 [] __rt_spin_lock+0x21/0x3c [] get_zone_pcp+0x20/0x29 [] free_hot_cold_page+0xdc/0x167 [] add_preempt_count+0x12/0xcc [] pgd_dtor+0x0/0x1 [] quicklist_trim+0xb7/0xe3 [] check_pgt_cache+0x19/0x1c [] free_pgtables+0x54/0x12c [] add_preempt_count+0x12/0xcc [] unmap_region+0xeb/0x13b BUG: scheduling while atomic: cc1/0x00000002/29745, CPU#0 [] __sched_text_start+0xb0/0x4fe [] try_to_wake_up+0x31b/0x326 [] add_preempt_count+0x12/0xcc [] add_preempt_count+0x12/0xcc [] schedule+0xe6/0x100 [] rt_spin_lock_slowlock+0xc5/0x145 [] __rt_spin_lock+0x3a/0x3c [] get_zone_pcp+0x20/0x29 [] free_hot_cold_page+0xdc/0x167 [] add_preempt_count+0x12/0xcc [] pgd_dtor+0x0/0x1 [] quicklist_trim+0xb7/0xe3 [] check_pgt_cache+0x19/0x1c [] free_pgtables+0x54/0x12c [] add_preempt_count+0x12/0xcc [] unmap_region+0xeb/0x13b [] do_munmap+0xea/0xff [] sys_munmap+0x31/0x40 [] syscall_call+0x7/0xb [] _shift_data_right_pages+0xb9/0xd1 ======================= --------------------------- | preempt count: 00000002 ] | 2-level deep critical section nesting: ---------------------------------------- .. [] .... quicklist_trim+0x1a/0xe3 .....[<00000000>] .. ( <= _stext+0x3fefff50/0x14) .. [] .... __sched_text_start+0x13/0x4fe .....[<00000000>] .. ( <= _stext+0x3fefff50/0x14) > Signed-Off-By: Daniel Walker > > Index: linux-2.6.22.1/kernel/sched.c > =================================================================== > --- linux-2.6.22.1.orig/kernel/sched.c 2007-07-22 16:47:37.000000000 +0000 > +++ linux-2.6.22.1/kernel/sched.c 2007-07-22 16:16:48.000000000 +0000 > @@ -4900,7 +4900,6 @@ asmlinkage long sys_sched_yield(void) > * no need to preempt or enable interrupts: > */ > spin_unlock_no_resched(&rq->lock); > - rcu_read_unlock(); > > __schedule(); > > > > - > To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html