[PATCH] selftests/tracing: Fix test_multiple_writes stall
From: Fushuai Wang <hidden>
Date: 2025-12-26 09:12:58
Also in:
linux-kselftest, lkml
Subsystem:
kernel selftest framework, the rest, tracing · Maintainers:
Shuah Khan, Shuah Khan, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
When /sys/kernel/tracing/buffer_size_kb is less than 12KB,
the test_multiple_writes test will stall and wait for more
input due to insufficient buffer space.
This patch check current buffer_size_kb value before the test.
If it is less than 12KB, it temporarily increase the buffer to
12KB, and restore the original value after the tests are completed.
Fixes: 37f46601383a ("selftests/tracing: Add basic test for trace_marker_raw file")
Signed-off-by: Fushuai Wang <redacted>
---
.../ftrace/test.d/00basic/trace_marker_raw.tc | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
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
index 7daf7292209e..216f87d89c3f 100644
--- a/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc
+++ b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc@@ -58,7 +58,7 @@ test_multiple_writes() { echo stop > trace_marker # Check to make sure the number of entries is the id (rounded up by 4) - awk '/.*: # [0-9a-f]* / { + awk -v ORIG="${ORIG}" '/.*: # [0-9a-f]* / { print; cnt = -1; for (i = 0; i < NF; i++) {
@@ -70,6 +70,7 @@ test_multiple_writes() { # The number of items is always rounded up by 4 cnt2 = int((cnt + 3) / 4) * 4; if (cnt2 != num) { + system("echo \""ORIG"\" > buffer_size_kb"); exit 1; } break;
@@ -89,6 +90,7 @@ 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" + echo $ORIG > buffer_size_kb exit_fail fi
@@ -99,9 +101,21 @@ test_buffer() { if write_buffer 0xdeadbeef $size ; then echo "Too big of write expected to fail but did not" + echo $ORIG > buffer_size_kb exit_fail fi } +ORIG=`cat buffer_size_kb` + +# test_multiple_writes test needs at least 12KB buffer +NEW_SIZE=12 + +if [ ${ORIG} -lt ${NEW_SIZE} ]; then + echo ${NEW_SIZE} > buffer_size_kb +fi + test_buffer test_multiple_writes + +echo $ORIG > buffer_size_kb
--
2.36.1