| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20231213093318.f30d29c5f80fff59571e62a7@kernel.org>
Date: Wed, 13 Dec 2023 09:33:18 +0900
From: Masami Hiramatsu (Google) <mhiramat@...nel.org>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
Linux Trace Kernel <linux-trace-kernel@...r.kernel.org>,
Masami Hiramatsu <mhiramat@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Shuah Khan <shuah@...nel.org>, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v2] tracing/selftests: Add test to test max subbuf size
with trace_marker
On Tue, 12 Dec 2023 15:16:32 -0500
Steven Rostedt <rostedt@...dmis.org> wrote:
> From: "Steven Rostedt (Google)" <rostedt@...dmis.org>
>
> Now that the trace_marker can write up to the max size of the sub buffer.
> Add a test to see if it actually can happen.
>
> The README is updated to state that the trace_marker writes can be broken
> up, and the test checks the README for that statement so that it does not
> fail on older kernels that does not support this.
I think it is better that the feature patch include README update or a separate
patch because it identifies the feature is implemented or not.
>
> If the README does not have the specified update, the test will still test
> if all the string is written, as that should work with older kernels.
>
> Cc: Shuah Khan <shuah@...nel.org>
> Cc: linux-kselftest@...r.kernel.org
> Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
> ---
> Changes since v1: https://lore.kernel.org/linux-trace-kernel/20231212135441.0337c3e9@gandalf.local.home/
>
> - Fix description as it was a cut and paste from the subbuffer size tests
> that are not added yet.
>
> kernel/trace/trace.c | 1 +
> .../ftrace/test.d/00basic/trace_marker.tc | 112 ++++++++++++++++++
> 2 files changed, 113 insertions(+)
> create mode 100755 tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 2f8d59834c00..cbfcdd882590 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -5595,6 +5595,7 @@ static const char readme_msg[] =
> " delta: Delta difference against a buffer-wide timestamp\n"
> " absolute: Absolute (standalone) timestamp\n"
> "\n trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
> + "\n May be broken into multiple events based on sub-buffer size.\n"
> "\n trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
> " tracing_cpumask\t- Limit which CPUs to trace\n"
> " instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
> diff --git a/tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc
> new file mode 100755
> index 000000000000..bf7f6f50c88a
> --- /dev/null
> +++ b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker.tc
> @@ -0,0 +1,112 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +# description: Basic tests on writing to trace_marker
> +# requires: trace_marker
> +# flags: instance
> +
> +get_buffer_data_size() {
> + sed -ne 's/^.*data.*size:\([0-9][0-9]*\).*/\1/p' events/header_page
> +}
> +
> +get_buffer_data_offset() {
> + sed -ne 's/^.*data.*offset:\([0-9][0-9]*\).*/\1/p' events/header_page
> +}
> +
> +get_event_header_size() {
> + type_len=`sed -ne 's/^.*type_len.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
> + time_len=`sed -ne 's/^.*time_delta.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
> + array_len=`sed -ne 's/^.*array.*:[^0-9]*\([0-9][0-9]*\).*/\1/p' events/header_event`
> + total_bits=$((type_len+time_len+array_len))
> + total_bits=$((total_bits+7))
> + echo $((total_bits/8))
> +}
> +
> +get_print_event_buf_offset() {
> + sed -ne 's/^.*buf.*offset:\([0-9][0-9]*\).*/\1/p' events/ftrace/print/format
> +}
> +
> +event_header_size=`get_event_header_size`
> +print_header_size=`get_print_event_buf_offset`
> +
> +# Find the README
> +README=""
> +if [ -f README ]; then
> + README="README"
> +# instance?
> +elif [ -f ../../README ]; then
> + README="../../README"
> +fi
> +
> +testone=0
> +if [ ! -z "$README" ]; then
> + if grep -q "May be broken into multiple events based on sub-buffer size" $README; then
> + testone=1
> + fi
> +fi
Hmm, this should be a common function if we see this pattern somewhere else.
> +
> +data_offset=`get_buffer_data_offset`
> +
> +marker_meta=$((event_header_size+print_header_size))
> +
> +make_str() {
> + cnt=$1
> + # subtract two for \n\0 as marker adds these
> + cnt=$((cnt-2))
> + printf -- 'X%.0s' $(seq $cnt)
> +}
> +
> +write_buffer() {
> + size=$1
> +
> + str=`make_str $size`
> +
> + # clear the buffer
> + echo > trace
> +
> + # write the string into the marker
> + echo -n $str > trace_marker
> +
> + echo $str
> +}
> +
> +test_buffer() {
> +
> + size=`get_buffer_data_size`
> + oneline_size=$((size-marker_meta))
> + echo size = $size
> + echo meta size = $marker_meta
> +
> + if [ $testone -eq 1 ]; then
> + echo oneline size = $oneline_size
> +
> + str=`write_buffer $oneline_size`
> +
> + # Should be in one single event
> + new_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: */,"");printf "%s", $0; exit}' trace`
> +
> + if [ "$new_str" != "$str" ]; then
> + exit fail;
> + fi
> + fi
Or, maybe we can split this part into another testcase.
Thank you,
> +
> + # Now add a little more the meta data overhead will overflow
> +
> + str=`write_buffer $size`
> +
> + # Make sure the line was broken
> + new_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: /,"");printf "%s", $0; exit}' trace`
> +
> + if [ "$new_str" = "$str" ]; then
> + exit fail;
> + fi
> +
> + # Make sure the entire line can be found
> + new_str=`awk ' /tracing_mark_write:/ { sub(/^.*tracing_mark_write: */,"");printf "%s", $0; }' trace`
> +
> + if [ "$new_str" != "$str" ]; then
> + exit fail;
> + fi
> +}
> +
> +test_buffer
> +
> --
> 2.42.0
>
--
Masami Hiramatsu (Google) <mhiramat@...nel.org>
Powered by blists - more mailing lists