From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933535Ab0J1N54 (ORCPT ); Thu, 28 Oct 2010 09:57:56 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:43228 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932830Ab0J1N4s (ORCPT ); Thu, 28 Oct 2010 09:56:48 -0400 X-Authority-Analysis: v=1.1 cv=+c36koQ5Dcj/1qolKHjtkYAGXvrVJRRiKMp+84F5sLg= c=1 sm=0 a=97Jt8JwOJ3IA:10 a=bbbx4UPp9XUA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=20KFwNOVAAAA:8 a=3nbZYyFuAAAA:8 a=meVymXHHAAAA:8 a=pKJDfCV8AVH237E5AGQA:9 a=hmfye8OkV17b-mfl81cA:7 a=hgWW_SGuo6VA4i-7bZUiwWv6InYA:4 a=jEp0ucaQiEUA:10 a=EvKJbDF4Ut8A:10 a=jeBq3FmKZ4MA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Message-Id: <20101028135647.429157214@goodmis.org> User-Agent: quilt/0.48-1 Date: Thu, 28 Oct 2010 09:55:51 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Frederic Weisbecker , Jason Baron , Masami Hiramatsu Subject: [PATCH 3/8] jump label: Fix error with preempt disable holding mutex References: <20101028135548.055490014@goodmis.org> Content-Disposition: inline; filename=0003-jump-label-Fix-error-with-preempt-disable-holding-mu.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt Kprobes and jump label were having a race between mutexes that was fixed by reordering the jump label. But this reordering moved the jump label mutex into a preempt disable location. This patch does a little fiddling to move the grabbing of the jump label mutex from inside the preempt disable section and still keep the order correct between the mutex and the kprobes lock. Reported-by: Ingo Molnar Cc: Jason Baron Cc: Masami Hiramatsu Signed-off-by: Steven Rostedt --- kernel/kprobes.c | 26 +++++++++++++------------- 1 files changed, 13 insertions(+), 13 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 9437e14..9737a76 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1145,17 +1145,13 @@ int __kprobes register_kprobe(struct kprobe *p) if (ret) return ret; - preempt_disable(); jump_label_lock(); + preempt_disable(); if (!kernel_text_address((unsigned long) p->addr) || in_kprobes_functions((unsigned long) p->addr) || ftrace_text_reserved(p->addr, p->addr) || - jump_label_text_reserved(p->addr, p->addr)) { - preempt_enable(); - jump_label_unlock(); - return -EINVAL; - } - jump_label_unlock(); + jump_label_text_reserved(p->addr, p->addr)) + goto fail_with_jump_label; /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */ p->flags &= KPROBE_FLAG_DISABLED; @@ -1169,10 +1165,9 @@ int __kprobes register_kprobe(struct kprobe *p) * We must hold a refcount of the probed module while updating * its code to prohibit unexpected unloading. */ - if (unlikely(!try_module_get(probed_mod))) { - preempt_enable(); - return -EINVAL; - } + if (unlikely(!try_module_get(probed_mod))) + goto fail_with_jump_label; + /* * If the module freed .init.text, we couldn't insert * kprobes in there. @@ -1180,11 +1175,11 @@ int __kprobes register_kprobe(struct kprobe *p) if (within_module_init((unsigned long)p->addr, probed_mod) && probed_mod->state != MODULE_STATE_COMING) { module_put(probed_mod); - preempt_enable(); - return -EINVAL; + goto fail_with_jump_label; } } preempt_enable(); + jump_label_unlock(); p->nmissed = 0; INIT_LIST_HEAD(&p->list); @@ -1226,6 +1221,11 @@ out: module_put(probed_mod); return ret; + +fail_with_jump_label: + preempt_enable(); + jump_label_unlock(); + return -EINVAL; } EXPORT_SYMBOL_GPL(register_kprobe); -- 1.7.1