5.15-stable review patch. If anyone has any objections, please let me know.
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From: Steven Rostedt rostedt@goodmis.org
[ Upstream commit 213879061a9c60200ba971330dbefec6df3b4a30 ]
The subsystem event test enables all "sched" events and makes sure there's at least 3 different events in the output. It used to cat the entire trace file to | wc -l, but on slow machines, that could last a very long time. To solve that, it was changed to just read the first 100 lines of the trace file. This can cause false failures as some events repeat so often, that the 100 lines that are examined could possibly be of only one event.
Instead, create an awk script that looks for 3 different events and will exit out after it finds them. This will find the 3 events the test looks for (eventually if it works), and still exit out after the test is satisfied and not cause slower machines to run forever.
Link: https://lore.kernel.org/r/20250721134212.53c3e140@batman.local.home Reported-by: Tengda Wu wutengda@huaweicloud.com Closes: https://lore.kernel.org/all/20250710130134.591066-1-wutengda@huaweicloud.com... Fixes: 1a4ea83a6e67 ("selftests/ftrace: Limit length in subsystem-enable tests") Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Shuah Khan skhan@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- .../ftrace/test.d/event/subsystem-enable.tc | 28 +++++++++++++++++-- 1 file changed, 26 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/ftrace/test.d/event/subsystem-enable.tc b/tools/testing/selftests/ftrace/test.d/event/subsystem-enable.tc index b7c8f29c09a9..65916bb55dfb 100644 --- a/tools/testing/selftests/ftrace/test.d/event/subsystem-enable.tc +++ b/tools/testing/selftests/ftrace/test.d/event/subsystem-enable.tc @@ -14,11 +14,35 @@ fail() { #msg exit_fail }
+# As reading trace can last forever, simply look for 3 different +# events then exit out of reading the file. If there's not 3 different +# events, then the test has failed. +check_unique() { + cat trace | grep -v '^#' | awk ' + BEGIN { cnt = 0; } + { + for (i = 0; i < cnt; i++) { + if (event[i] == $5) { + break; + } + } + if (i == cnt) { + event[cnt++] = $5; + if (cnt > 2) { + exit; + } + } + } + END { + printf "%d", cnt; + }' +} + echo 'sched:*' > set_event
yield
-count=`head -n 100 trace | grep -v ^# | awk '{ print $5 }' | sort -u | wc -l` +count=`check_unique` if [ $count -lt 3 ]; then fail "at least fork, exec and exit events should be recorded" fi @@ -29,7 +53,7 @@ echo 1 > events/sched/enable
yield
-count=`head -n 100 trace | grep -v ^# | awk '{ print $5 }' | sort -u | wc -l` +count=`check_unique` if [ $count -lt 3 ]; then fail "at least fork, exec and exit events should be recorded" fi