From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757542AbZCRL51 (ORCPT ); Wed, 18 Mar 2009 07:57:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757398AbZCRL5H (ORCPT ); Wed, 18 Mar 2009 07:57:07 -0400 Received: from hera.kernel.org ([140.211.167.34]:55512 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757202AbZCRL5F (ORCPT ); Wed, 18 Mar 2009 07:57:05 -0400 Date: Wed, 18 Mar 2009 11:54:28 GMT From: Ananth N Mavinakayanahalli To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, jkenisto@us.ibm.com, torvalds@linux-foundation.org, ananth@in.ibm.com, bharata@linux.vnet.ibm.com, akpm@linux-foundation.org, tglx@linutronix.de, mhiramat@redhat.com, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, jkenisto@us.ibm.com, torvalds@linux-foundation.org, ananth@in.ibm.com, bharata@linux.vnet.ibm.com, akpm@linux-foundation.org, tglx@linutronix.de, mhiramat@redhat.com, mingo@elte.hu In-Reply-To: <20090318113621.GB4129@in.ibm.com> References: <20090318113621.GB4129@in.ibm.com> Subject: [tip:tracing/kprobes] kprobes: Fix locking imbalance in kretprobes Message-ID: Git-Commit-ID: f02b8624fedca39886b0eef770dca70c2f0749b3 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Wed, 18 Mar 2009 11:54:30 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: f02b8624fedca39886b0eef770dca70c2f0749b3 Gitweb: http://git.kernel.org/tip/f02b8624fedca39886b0eef770dca70c2f0749b3 Author: Ananth N Mavinakayanahalli AuthorDate: Wed, 18 Mar 2009 17:06:21 +0530 Commit: Ingo Molnar CommitDate: Wed, 18 Mar 2009 12:51:16 +0100 kprobes: Fix locking imbalance in kretprobes 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 Cc: Masami Hiramatsu Cc: Jim Keniston Cc: Linus Torvalds Cc: Andrew Morton Cc: [2.6.29.x, 2.6.28.x, 2.6.27.x] LKML-Reference: <20090318113621.GB4129@in.ibm.com> Signed-off-by: Ingo Molnar --- kernel/kprobes.c | 4 +--- 1 files changed, 1 insertions(+), 3 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 479d4d5..5016bfb 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -919,10 +919,8 @@ static int __kprobes pre_handler_kretprobe(struct kprobe *p, 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);