From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759442AbYHUSyw (ORCPT ); Thu, 21 Aug 2008 14:54:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753468AbYHUSyn (ORCPT ); Thu, 21 Aug 2008 14:54:43 -0400 Received: from e28smtp03.in.ibm.com ([59.145.155.3]:49221 "EHLO e28esmtp03.in.ibm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753893AbYHUSyl (ORCPT ); Thu, 21 Aug 2008 14:54:41 -0400 Message-ID: <48ADB9E8.7060906@linux.vnet.ibm.com> Date: Fri, 22 Aug 2008 00:24:32 +0530 From: Kamalesh Babulal User-Agent: Thunderbird 1.5.0.14ubu (X11/20080724) MIME-Version: 1.0 To: Vegard Nossum CC: jay kumar , David Howells , linux-kernel@vger.kernel.org, linux-next@vger.kernel.org Subject: Re: Bug: "bad unlock balance detected" 2.6.27-rc3-next-20080820 References: <6f31812b0808210004i63b3273ehf65ce9eb139256f0@mail.gmail.com> <19f34abd0808210110s4dd2ec12r6d3044e45a21d67@mail.gmail.com> In-Reply-To: <19f34abd0808210110s4dd2ec12r6d3044e45a21d67@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Vegard Nossum wrote: > On Thu, Aug 21, 2008 at 9:04 AM, jay kumar wrote: >> While testing 2.6.27-rc3-next-20080820 , i observed this "BUG:bad >> unlock balance detected" during boot time >> >> commit 765d4840cc9cca98c0cc4ff4764608780c3265f6 >> Author: Stephen Rothwell >> Date: Wed Aug 20 18:59:47 2008 +1000 >> >> >> Bug info: >> >> [ 0.140173] ===================================== >> [ 0.145977] [ BUG: bad unlock balance detected! ] >> [ 0.145977] ------------------------------------- >> [ 0.145977] khelper/12 is trying to release lock (&p->cred_exec_mutex) at: >> [ 0.146977] [] mutex_unlock+0xd/0xf >> [ 0.146977] but there are no more locks to release! >> [ 0.146977] >> [ 0.146977] other info that might help us debug this: >> [ 0.146977] no locks held by khelper/12. >> [ 0.146977] >> [ 0.146977] stack backtrace: >> [ 0.146977] Pid: 12, comm: khelper Not tainted 2.6.27-rc3-next-20080820 #13 >> [ 0.146977] [] ? mutex_unlock+0xd/0xf >> [ 0.146977] [] print_unlock_inbalance_bug+0xa5/0xb2 >> [ 0.146977] [] ? mutex_unlock+0xd/0xf >> [ 0.146977] [] lock_release+0x8f/0x186 >> [ 0.146977] [] __mutex_unlock_slowpath+0x9b/0xed >> [ 0.146977] [] mutex_unlock+0xd/0xf >> [ 0.146977] [] free_bprm+0x24/0x39 >> [ 0.146977] [] do_execve+0x1e5/0x1fb >> [ 0.146977] [] sys_execve+0x2e/0x51 >> [ 0.146977] [] syscall_call+0x7/0xb >> [ 0.146977] [] ? kernel_execve+0x1c/0x21 >> [ 0.146977] [] ? ____call_usermodehelper+0x0/0x129 >> [ 0.146977] [] ? ____call_usermodehelper+0x11f/0x129 >> [ 0.146977] [] ? ____call_usermodehelper+0x0/0x129 >> [ 0.146977] [] ? kernel_thread_helper+0x7/0x10 >> [ 0.146977] ======================= > > (config clipped) > > Hi, > > Thanks for the report. The error comes from > > commit d9a939fb80ef390b78b3c801f668bd1e35ebc970 > Author: David Howells > Date: Thu Aug 7 20:02:20 2008 +1000 > > CRED: Make execve() take advantage of copy-on-write credentials > > (Added to Cc. I guess it's also nice to Cc linux-next on errors in -next code.) > > I couldn't reproduce your original failure, but I've attempted to fix > it by reordering the mutex unlock and bprm free and removing the > extraneous unlock (see attached patch; it boots for me without > errors). > > > Vegard > Hi, Thanks, the patch fixes the "bad unlock balance" warning I was hitting with the next-20080821 patchset. Tested-by: Kamalesh Babulal -- Thanks & Regards, Kamalesh Babulal, Linux Technology Center, IBM, ISTL.