From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757063AbZCRLga (ORCPT ); Wed, 18 Mar 2009 07:36:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755987AbZCRLgU (ORCPT ); Wed, 18 Mar 2009 07:36:20 -0400 Received: from e9.ny.us.ibm.com ([32.97.182.139]:55798 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755547AbZCRLgT (ORCPT ); Wed, 18 Mar 2009 07:36:19 -0400 Date: Wed, 18 Mar 2009 17:06:21 +0530 From: Ananth N Mavinakayanahalli To: Linus Torvalds , Andrew Morton Cc: lkml , Masami Hiramatsu , Jim Keniston , bharata@linux.vnet.ibm.com Subject: [PATCH] Kprobes: Fix locking imbalance in kretprobes Message-ID: <20090318113621.GB4129@in.ibm.com> Reply-To: ananth@in.ibm.com MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Fix locking imbalance in kretprobes: ===================================== [ BUG: bad unlock balance detected! ] ------------------------------------- kthreadd/2 is trying to release lock (&rp->lock) at: [] pre_handler_kretprobe+0xea/0xf4 but there are no more locks to release! other info that might help us debug this: 1 lock held by kthreadd/2: #0: (rcu_read_lock){..--}, at: [] __atomic_notifier_call_chain+0x0/0x5a stack backtrace: Pid: 2, comm: kthreadd Not tainted 2.6.29-rc8 #1 Call Trace: [] ? printk+0xf/0x17 [] ? pre_handler_kretprobe+0xea/0xf4 [] print_unlock_inbalance_bug+0xc3/0xce [] ? clocksource_read+0x7/0xa [] ? getnstimeofday+0x5f/0xf6 [] ? register_lock_class+0x17/0x293 [] ? mark_lock+0x1e/0x30b [] ? tick_dev_program_event+0x4a/0xbc [] ? __slab_alloc+0xa5/0x415 [] ? pre_handler_kretprobe+0x28/0xf4 [] ? pre_handler_kretprobe+0xea/0xf4 [] lock_release_non_nested+0xa4/0x1a5 [] ? pre_handler_kretprobe+0xea/0xf4 [] lock_release+0x141/0x166 [] _spin_unlock_irqrestore+0x19/0x50 [] pre_handler_kretprobe+0xea/0xf4 [] kprobe_exceptions_notify+0x1c9/0x43e [] notifier_call_chain+0x26/0x48 [] __atomic_notifier_call_chain+0x37/0x5a [] ? __atomic_notifier_call_chain+0x0/0x5a [] atomic_notifier_call_chain+0xc/0xe [] notify_die+0x2d/0x2f [] do_int3+0x1f/0x71 [] int3+0x2c/0x34 [] ? do_fork+0x1/0x288 [] ? kernel_thread+0x71/0x79 [] ? kthread+0x0/0x60 [] ? kthread+0x0/0x60 [] ? kernel_thread_helper+0x0/0x10 [] kthreadd+0xac/0x148 [] ? kthreadd+0x0/0x148 [] kernel_thread_helper+0x7/0x10 Signed-off-by: Ananth N Mavinakayanahalli Tested-by: Bharata B Rao --- kernel/kprobes.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) Index: utrace-16mar/kernel/kprobes.c =================================================================== --- utrace-16mar.orig/kernel/kprobes.c +++ utrace-16mar/kernel/kprobes.c @@ -912,10 +912,8 @@ static int __kprobes pre_handler_kretpro ri->rp = rp; ri->task = current; - if (rp->entry_handler && rp->entry_handler(ri, regs)) { - spin_unlock_irqrestore(&rp->lock, flags); + if (rp->entry_handler && rp->entry_handler(ri, regs)) return 0; - } arch_prepare_kretprobe(ri, regs);