From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757852AbYLPVPb (ORCPT ); Tue, 16 Dec 2008 16:15:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751960AbYLPVPX (ORCPT ); Tue, 16 Dec 2008 16:15:23 -0500 Received: from mail-fx0-f20.google.com ([209.85.220.20]:41795 "EHLO mail-fx0-f20.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751644AbYLPVPW (ORCPT ); Tue, 16 Dec 2008 16:15:22 -0500 X-Greylist: delayed 378 seconds by postgrey-1.27 at vger.kernel.org; Tue, 16 Dec 2008 16:15:21 EST DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :content-type:content-transfer-encoding; b=ENgi8P7FHzmbghvHybOE1JZCYKLDHP+PTnwJIf1pxFqZDzpQ5oPuHAiIO+Of89PX4p YO6g40HZz3ynSmGSfS74KBuyRnKFplx6U1glCsmvsqrZ6Sht/epegVT9PGaM9edR1Rxi QZndVoIr/msA3fV3KUv3L6pZpk0vVQBunXtf4= Message-ID: <494818EA.7080807@gmail.com> Date: Tue, 16 Dec 2008 22:08:58 +0100 From: Frederic Weisbecker User-Agent: Thunderbird 2.0.0.18 (X11/20081125) MIME-Version: 1.0 To: Ingo Molnar CC: Steven Rostedt , Linux Kernel Subject: [PATCH] tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp() Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Impact: prevent a trace recursion After some tests with function graph tracer under x86-32, I saw some recursions caused by ring_buffer_time_stamp() that calls preempt_enable_no_notrace() which calls preempt_schedule() which is traced itself. This patch re-enables preemption without rescheduling. Cc: Steven Rostedt Signed-off-by: Frederic Weisbecker --- kernel/trace/ring_buffer.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 822fcd4..a775e46 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -109,7 +109,7 @@ u64 ring_buffer_time_stamp(int cpu) preempt_disable_notrace(); /* shift to debug/test normalization and TIME_EXTENTS */ time = sched_clock() << DEBUG_SHIFT; - preempt_enable_notrace(); + preempt_enable_no_resched_notrace(); return time; } -- 1.6.0.4