From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934111AbdDGRG1 (ORCPT ); Fri, 7 Apr 2017 13:06:27 -0400 Received: from mail.kernel.org ([198.145.29.136]:40362 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932576AbdDGRGT (ORCPT ); Fri, 7 Apr 2017 13:06:19 -0400 Date: Fri, 7 Apr 2017 13:06:15 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , "Paul E. McKenney" , Mathieu Desnoyers Subject: [PATCH 7/5] tracing: Make sure rcu_irq_enter() can work for trace_*_rcuidle() trace events Message-ID: <20170407130615.2309b96d@gandalf.local.home> In-Reply-To: <20170407140106.051135969@goodmis.org> References: <20170407140106.051135969@goodmis.org> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-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 From: "Steven Rostedt (VMware)" Stack tracing discovered that there's a small location inside the RCU infrastructure that calling rcu_irq_enter() does not work. As trace events use rcu_irq_enter() it must make sure that it is functionable. A check against rcu_irq_enter_disabled() is added with a WARN_ON_ONCE() as no trace event should ever be used in that part of RCU. If the warning is triggered, then the trace event is ignored. Cc: Mathieu Desnoyers Signed-off-by: Steven Rostedt (VMware) --- include/linux/tracepoint.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index f72fcfe..8baef96 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -159,6 +159,8 @@ extern void syscall_unregfunc(void); TP_PROTO(data_proto), \ TP_ARGS(data_args), \ TP_CONDITION(cond), \ + if (WARN_ON_ONCE(rcu_irq_enter_disabled())) \ + return; \ rcu_irq_enter_irqson(), \ rcu_irq_exit_irqson()); \ } -- 2.9.3