From patchwork Wed Dec 2 17:00:05 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 551603 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 87F9814076E; Thu, 3 Dec 2015 04:08:25 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1a4AtD-0000i3-HF; Wed, 02 Dec 2015 17:08:23 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1a4An1-0005BB-Th for kernel-team@lists.ubuntu.com; Wed, 02 Dec 2015 17:01:59 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1a4Amz-0003Wo-QT; Wed, 02 Dec 2015 17:01:57 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1a4Amx-0005i3-J5; Wed, 02 Dec 2015 09:01:55 -0800 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.19.y-ckt 154/164] tracepoints: Fix documentation of RCU lockdep checks Date: Wed, 2 Dec 2015 09:00:05 -0800 Message-Id: <1449075615-20754-155-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1449075615-20754-1-git-send-email-kamal@canonical.com> References: <1449075615-20754-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Cc: Kamal Mostafa , Dave Hansen , Mathieu Desnoyers , Steven Rostedt X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.19.8-ckt11 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Mathieu Desnoyers commit a15920bea0428cd22291637f6c72542b1843e65f upstream. The documentation on top of __DECLARE_TRACE() does not match its implementation since the condition check has been added to the RCU lockdep checks. Update the documentation to match its implementation. Link: http://lkml.kernel.org/r/1446504164-21563-1-git-send-email-mathieu.desnoyers@efficios.com CC: Dave Hansen Fixes: a05d59a56733 "tracing: Add condition check to RCU lockdep checks" Signed-off-by: Mathieu Desnoyers Signed-off-by: Steven Rostedt Signed-off-by: Kamal Mostafa --- include/linux/tracepoint.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index c728513..37917e4 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -159,10 +159,11 @@ extern void syscall_unregfunc(void); * structure. Force alignment to the same alignment as the section start. * * When lockdep is enabled, we make sure to always do the RCU portions of - * the tracepoint code, regardless of whether tracing is on or we match the - * condition. This lets us find RCU issues triggered with tracepoints even - * when this tracepoint is off. This code has no purpose other than poking - * RCU a bit. + * the tracepoint code, regardless of whether tracing is on. However, + * don't check if the condition is false, due to interaction with idle + * instrumentation. This lets us find RCU issues triggered with tracepoints + * even when this tracepoint is off. This code has no purpose other than + * poking RCU a bit. */ #define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \ extern struct tracepoint __tracepoint_##name; \