From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11A46C83000 for ; Wed, 29 Apr 2020 23:24:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EAC6C2082E for ; Wed, 29 Apr 2020 23:24:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726935AbgD2XYi (ORCPT ); Wed, 29 Apr 2020 19:24:38 -0400 Received: from 8.mo7.mail-out.ovh.net ([46.105.77.114]:56326 "EHLO 8.mo7.mail-out.ovh.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726511AbgD2XYi (ORCPT ); Wed, 29 Apr 2020 19:24:38 -0400 X-Greylist: delayed 8401 seconds by postgrey-1.27 at vger.kernel.org; Wed, 29 Apr 2020 19:24:38 EDT Received: from player693.ha.ovh.net (unknown [10.110.115.113]) by mo7.mail-out.ovh.net (Postfix) with ESMTP id C92DC16096E for ; Wed, 29 Apr 2020 22:58:25 +0200 (CEST) Received: from sk2.org (82-65-25-201.subs.proxad.net [82.65.25.201]) (Authenticated sender: steve@sk2.org) by player693.ha.ovh.net (Postfix) with ESMTPSA id 025B411DB2FC6; Wed, 29 Apr 2020 20:58:15 +0000 (UTC) From: Stephen Kitt To: Jonathan Corbet , Mauro Carvalho Chehab , linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Steven Rostedt , Stephen Kitt Subject: [PATCH v2 1/2] docs: sysctl/kernel: document ftrace entries Date: Wed, 29 Apr 2020 22:57:56 +0200 Message-Id: <20200429205757.8677-1-steve@sk2.org> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Ovh-Tracer-Id: 16893283679029906821 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeduhedrieefgdduheegucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecuhedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephffvufffkffoggfgsedtkeertdertddtnecuhfhrohhmpefuthgvphhhvghnucfmihhtthcuoehsthgvvhgvsehskhdvrdhorhhgqeenucggtffrrghtthgvrhhnpeetgedugfelkeeikeetgeegteevfeeufeetuefgudeiiedthfehtdeffeekvdeffeenucfkpheptddrtddrtddrtddpkedvrdeihedrvdehrddvtddunecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmohguvgepshhmthhpqdhouhhtpdhhvghlohepphhlrgihvghrieelfedrhhgrrdhovhhhrdhnvghtpdhinhgvtheptddrtddrtddrtddpmhgrihhlfhhrohhmpehsthgvvhgvsehskhdvrdhorhhgpdhrtghpthhtoheplhhinhhugidqughotgesvhhgvghrrdhkvghrnhgvlhdrohhrgh Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Based on the ftrace documentation, the tp_printk boot parameter documentation, and the implementation in kernel/trace/trace.c. Signed-off-by: Stephen Kitt --- Changes since v2: - spelling and grammar fixes in ftrace_dump_on_oops ("outputing it" -> "outputting them") - "and::" in a single line in tracepoint_printk Documentation/admin-guide/sysctl/kernel.rst | 48 +++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 82bfd5892663..b1ad4c86274d 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -265,6 +265,27 @@ domain names are in general different. For a detailed discussion see the ``hostname(1)`` man page. +ftrace_dump_on_oops +=================== + +Determines whether ``ftrace_dump()`` should be called on an oops (or +kernel panic). This will output the contents of the ftrace buffers to +the console. This is very useful for capturing traces that lead to +crashes and outputting them to a serial console. + += =================================================== +0 Disabled (default). +1 Dump buffers of all CPUs. +2 Dump the buffer of the CPU that triggered the oops. += =================================================== + + +ftrace_enabled, stack_tracer_enabled +==================================== + +See :doc:`/trace/ftrace`. + + hardlockup_all_cpu_backtrace ============================ @@ -1191,6 +1212,33 @@ If a value outside of this range is written to ``threads-max`` an ``EINVAL`` error occurs. +traceoff_on_warning +=================== + +When set, disables tracing (see :doc:`/trace/ftrace`) when a +``WARN()`` is hit. + + +tracepoint_printk +================= + +When tracepoints are sent to printk() (enabled by the ``tp_printk`` +boot parameter), this entry provides runtime control:: + + echo 0 > /proc/sys/kernel/tracepoint_printk + +will stop tracepoints from being sent to printk(), and:: + + echo 1 > /proc/sys/kernel/tracepoint_printk + +will send them to printk() again. + +This only works if the kernel was booted with ``tp_printk`` enabled. + +See :doc:`/admin-guide/kernel-parameters` and +:doc:`/trace/boottime-trace`. + + unknown_nmi_panic ================= -- 2.20.1