From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754546AbdEQRus (ORCPT ); Wed, 17 May 2017 13:50:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:41774 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754344AbdEQRup (ORCPT ); Wed, 17 May 2017 13:50:45 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0D51623986 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=mhiramat@kernel.org Date: Thu, 18 May 2017 02:50:36 +0900 From: Masami Hiramatsu To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Peter Zijlstra , Ingo Molnar , Mathieu Desnoyers , "Paul E. McKenney" , Masami Hiramatsu Subject: Re: [RFC][PATCH 3/5] kprobes: Take get_online_cpus() before taking jump_label_lock() Message-Id: <20170518025036.5bd900cdab5c3998b3d32c4d@kernel.org> In-Reply-To: <20170512172450.127400191@goodmis.org> References: <20170512171544.100715273@goodmis.org> <20170512172450.127400191@goodmis.org> X-Mailer: Sylpheed 3.5.0 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 12 May 2017 13:15:47 -0400 Steven Rostedt wrote: > From: "Steven Rostedt (VMware)" > > jump_label_lock() is taken under get_online_cpus(). Make sure that kprobes > follows suit. BTW, register_aggr_kprobe() is called under kprobe_mutex locked. Is that OK? Thank you, > > Signed-off-by: Steven Rostedt (VMware) > --- > kernel/kprobes.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index d733479a10ee..57cf73aef488 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1294,13 +1294,13 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) > int ret = 0; > struct kprobe *ap = orig_p; > > - /* For preparing optimization, jump_label_text_reserved() is called */ > - jump_label_lock(); > /* > * Get online CPUs to avoid text_mutex deadlock.with stop machine, > * which is invoked by unoptimize_kprobe() in add_new_kprobe() > */ > get_online_cpus(); > + /* For preparing optimization, jump_label_text_reserved() is called */ > + jump_label_lock(); > mutex_lock(&text_mutex); > > if (!kprobe_aggrprobe(orig_p)) { > @@ -1348,8 +1348,8 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p) > > out: > mutex_unlock(&text_mutex); > - put_online_cpus(); > jump_label_unlock(); > + put_online_cpus(); > > if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) { > ap->flags &= ~KPROBE_FLAG_DISABLED; > -- > 2.10.2 > > -- Masami Hiramatsu