Re: [PATCH] selftests/tracing: Add basic test for trace_marker_raw file

On Tue, 14 Oct 2025 14:51:49 -0400 Steven Rostedt rostedt@goodmis.org wrote:

From: Steven Rostedt rostedt@goodmis.org

Commit 64cf7d058a00 ("tracing: Have trace_marker use per-cpu data to read user space") made an update that fixed both trace_marker and trace_marker_raw. But the small difference made to trace_marker_raw had a blatant bug in it that any basic testing would have uncovered. Unfortunately, the self tests have tests for trace_marker but nothing for trace_marker_raw which allowed the bug to get upstream.

Add basic selftests to test trace_marker_raw so that this doesn't happen again.

Looks good to me.

Acked-by: Masami Hiramatsu (Google) mhiramat@kernel.org

Thanks!

Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org

.../ftrace/test.d/00basic/trace_marker_raw.tc | 107 ++++++++++++++++++ 1 file changed, 107 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc

diff --git a/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc new file mode 100644 index 000000000000..7daf7292209e --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc @@ -0,0 +1,107 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Basic tests on writing to trace_marker_raw +# requires: trace_marker_raw +# flags: instance

+is_little_endian() {

• if lscpu | grep -q 'Little Endian'; then

• echo 1;
  

• else

• echo 0;
  

• fi

+}

+little=`is_little_endian`

+make_str() {

• id=$1
• cnt=$2
• if [ $little -eq 1 ]; then

• val=`printf "\\%03o\\%03o\\%03o\\%03o" \
  

• 	$(($id & 0xff)) \
  

• 	$((($id >> 8) & 0xff)) \
  

• 	$((($id >> 16) & 0xff)) \
  

• 	$((($id >> 24) & 0xff))`
  

• else

• val=`printf "\\%03o\\%03o\\%03o\\%03o" \
  

• 	$((($id >> 24) & 0xff)) \
  

• 	$((($id >> 16) & 0xff)) \
  

• 	$((($id >> 8) & 0xff)) \
  

• 	$(($id & 0xff))`
  

• fi
• data=`printf -- 'X%.0s' $(seq $cnt)`
• printf "${val}${data}"

+}

+write_buffer() {

• id=$1
• size=$2
• # write the string into the raw marker
• make_str $id $size > trace_marker_raw

+}

+test_multiple_writes() {

• # Write a bunch of data where the id is the count of
• # data to write
• for i in `seq 1 10` `seq 101 110` `seq 1001 1010`; do

• write_buffer $i $i
  

• done
• # add a little buffer
• echo stop > trace_marker
• # Check to make sure the number of entries is the id (rounded up by 4)
• awk '/.*: # [0-9a-f]* / {

• 	print;
  

• 	cnt = -1;
  

• 	for (i = 0; i < NF; i++) {
  

• 		# The counter is after the "#" marker
  

• 		if ( $i == "#" ) {
  

• 			i++;
  

• 			cnt = strtonum("0x" $i);
  

• 			num = NF - (i + 1);
  

• 			# The number of items is always rounded up by 4
  

• 			cnt2 = int((cnt + 3) / 4) * 4;
  

• 			if (cnt2 != num) {
  

• 				exit 1;
  

• 			}
  

• 			break;
  

• 		}
  

• 	}
  

• }
  

• // { if (NR > 30) { exit 0; } } ' trace_pipe;

+}

+get_buffer_data_size() {

• sed -ne 's/^.*data.*size:([0-9][0-9]*).*/\1/p' events/header_page

+}

+test_buffer() {

• # The id must be four bytes, test that 3 bytes fails a write
• if echo -n abc > ./trace_marker_raw ; then

• echo "Too small of write expected to fail but did not"
  

• exit_fail
  

• fi
• size=`get_buffer_data_size`
• echo size = $size
• # Now add a little more than what it can handle
• if write_buffer 0xdeadbeef $size ; then

• echo "Too big of write expected to fail but did not"
  

• exit_fail
  

• fi

+}

+test_buffer

+test_multiple_writes

2.51.0