Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757522Ab2ECPmX (ORCPT ); Thu, 3 May 2012 11:42:23 -0400 Received: from e39.co.us.ibm.com ([32.97.110.160]:36697 "EHLO e39.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754312Ab2ECPmW (ORCPT ); Thu, 3 May 2012 11:42:22 -0400 Date: Thu, 3 May 2012 08:41:40 -0700 From: "Paul E. McKenney" To: Sasha Levin Cc: "linux-kernel@vger.kernel.org List" Subject: Re: rcu: BUG on exit_group Message-ID: <20120503154140.GA2592@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER x-cbid: 12050315-4242-0000-0000-0000018B3785 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2898 Lines: 60 On Thu, May 03, 2012 at 10:57:19AM +0200, Sasha Levin wrote: > Hi Paul, > > I've hit a BUG similar to the schedule_tail() one when. It happened > when I've started fuzzing exit_group() syscalls, and all of the traces > are starting with exit_group() (there's a flood of them). > > I've verified that it indeed BUGs due to the rcu preempt count. Hello, Sasha, Which version of -next are you using? I did some surgery on this yesterday based on some bugs Hugh Dickins tracked down, so if you are using something older, please move to the current -next. Thanx, Paul > Here's one of the BUG()s: > > [ 83.820976] BUG: sleeping function called from invalid context at > kernel/mutex.c:269 > [ 83.827870] in_atomic(): 0, irqs_disabled(): 0, pid: 4506, name: trinity > [ 83.832154] 1 lock held by trinity/4506: > [ 83.834224] #0: (rcu_read_lock){.+.+..}, at: [] > munlock_vma_page+0x197/0x200 > [ 83.839310] Pid: 4506, comm: trinity Tainted: G W > 3.4.0-rc5-next-20120503-sasha-00002-g09f55ae-dirty #108 > [ 83.849418] Call Trace: > [ 83.851182] [] __might_sleep+0x1f8/0x210 > [ 83.854076] [] mutex_lock_nested+0x2a/0x50 > [ 83.857120] [] try_to_unmap_file+0x40/0x2f0 > [ 83.860242] [] ? _raw_spin_unlock_irq+0x2b/0x80 > [ 83.863423] [] ? sub_preempt_count+0xae/0xf0 > [ 83.866347] [] ? _raw_spin_unlock_irq+0x59/0x80 > [ 83.869570] [] try_to_munlock+0x6a/0x80 > [ 83.872667] [] munlock_vma_page+0xd6/0x200 > [ 83.875646] [] ? munlock_vma_page+0x197/0x200 > [ 83.878798] [] munlock_vma_pages_range+0x8f/0xd0 > [ 83.882235] [] exit_mmap+0x5a/0x160 > [ 83.884880] [] ? exit_mm+0x10b/0x130 > [ 83.887508] [] ? __lock_release+0x1ba/0x1d0 > [ 83.890399] [] mmput+0x81/0xe0 > [ 83.892966] [] exit_mm+0x11b/0x130 > [ 83.895640] [] ? _raw_spin_unlock_irq+0x59/0x80 > [ 83.898943] [] do_exit+0x263/0x460 > [ 83.901700] [] do_group_exit+0xa1/0xe0 > [ 83.907366] [] sys_exit_group+0x12/0x20 > [ 83.912450] [] system_call_fastpath+0x16/0x1b > -- > 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/ > -- 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/