[PATCH v2] selftests/tracing: Fix test_multiple_writes stall
From: Fushuai Wang <hidden>
Date: 2025-12-27 04:18:47
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.
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")
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Fushuai Wang <redacted>
---
V1 -> V2: Restore buffer_size_kb outside of awk script.
.../ftrace/test.d/00basic/trace_marker_raw.tc | 18 +++++++++++++++++-
1 file changed, 17 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..a2c42e13f614 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@@ -89,6 +89,7 @@ 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 +100,24 @@ 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 +if ! test_multiple_writes; then + echo ${ORIG} > buffer_size_kb + exit_fail +fi + +echo ${ORIG} > buffer_size_kb
--
2.36.1