On Mon, 14 Aug 2023 10:59:18 +0800
Yipeng Zou <zouyipeng@xxxxxxxxxx> wrote:
> So I directly dump the trace file before md5sum, the diff shows that:
>
> [root@localhost]# diff trace_1.log trace_2.log -y --suppress-common-lines
> dockerd-12285 [036] d.... 18385.510290: sched_stat | <...>-12285 [036] d.... 18385.510290: sched_stat
> dockerd-12285 [036] d.... 18385.510291: sched_swit | <...>-12285 [036] d.... 18385.510291: sched_swit
> <...>-740 [044] d.... 18385.602859: sched_stat | kworker/44:1-740 [044] d.... 18385.602859: sched_stat
> <...>-740 [044] d.... 18385.602860: sched_swit | kworker/44:1-740 [044] d.... 18385.602860: sched_swit
So the problem is the <..> being added?
>
> And we can see that the saved_cmdlines in kernel was changed.
>
> So Maybe there is no safe to use md5sum here to verify whether
> the file whether it has changed.
>
> >From my point of view, we only need to verify traceoff event
> is valid there.
>
> Maybe it is enough to check first that the tracing_on equals 0,
> and then check that the total number of rows of trace does not
> increase?
>
> Fixes: d87b29179aa0 ("selftests: ftrace: Use md5sum to take less time of checking logs")
> Signed-off-by: Yipeng Zou <zouyipeng@xxxxxxxxxx>
> ---
> .../test.d/ftrace/func_traceonoff_triggers.tc | 16 ++++------------
> 1 file changed, 4 insertions(+), 12 deletions(-)
>
> diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc
> index aee22289536b..180c60605d7b 100644
> --- a/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc
> +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc
> @@ -77,25 +77,17 @@ if [ $cnt -ne 1 ]; then
> fail "Did not find traceoff trigger"
> fi
>
> -cnt=`cnt_trace`
> -sleep $SLEEP_TIME
> -cnt2=`cnt_trace`
> -
> -if [ $cnt -ne $cnt2 ]; then
> - fail "Tracing is not stopped"
> -fi
> -
> on=`cat tracing_on`
> if [ $on != "0" ]; then
> fail "Tracing is not off"
> fi
>
> -csum1=`md5sum trace`
What about just changing the above to:
# Can not rely on names being around as they are only cached
csum1=`cat trace | sed -e 's/^ *[^ ]*\(-[0-9][0-9]*\)/\1/' | md5sum`
> +cnt=`cnt_trace`
> sleep $SLEEP_TIME
> -csum2=`md5sum trace`
And this:
csum2=`cat trace | sed -e 's/^ *[^ ]*\(-[0-9][0-9]*\)/\1/' | md5sum`
That will strip off the names an leave just the -[PID]... part of the line?
-- Steve
> +cnt2=`cnt_trace`
>
> -if [ "$csum1" != "$csum2" ]; then
> - fail "Tracing file is still changing"
> +if [ $cnt -ne $cnt2 ]; then
> + fail "Tracing is not stopped"
> fi
>
> clear_trace
