Messages in this thread | | | Date | Thu, 20 Oct 2022 00:46:07 +0900 | From | Masami Hiramatsu (Google) <> | Subject | Re: [PATCH] selftests/ftrace: Limit number of lines processed in 'trace' |
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On Wed, 19 Oct 2022 15:15:09 +0530 "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote:
> Steven Rostedt wrote: > > On Wed, 19 Oct 2022 00:19:49 +0900 > > Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote: > > > >> > You need to make sure that the "pause-on-trace" option is set or tracing_on > >> > is set to 0 (disabled). Otherwise, if the tracing is still active, then the > >> > reading of the trace file could potentially never end. > >> > >> initialize_ftrace() does this setting. So it must be set. > >> If you run the ftracetest on old kernel, this feature is not there and > >> it may cause a trouble. Naveen, can you clarify it? > > Yes, the change to not pause on opening the trace file looks to be the > problem. > > > > > But for old kernels that do not have "pause-on-trace" it should be the > > default. The "pause-on-trace" was added when the default was changed to not > > pause the trace while reading it. > > It looks like the kernel patch was picked up, but Masami's patch for the > selftest wasn't backported. I have requested a test with that applied.
Good! That should be backported too. BTW, which kernel version do you test?
> > Separately, before I saw your response, I came up with the below patch > to update the selftests to disable tracing before reading the trace > file. I have also requested this to be tested.
Yeah, OK. This also looks OK to me.
Thanks,
> > > - Naveen > > --- > .../selftests/ftrace/test.d/ftrace/fgraph-filter-stack.tc | 4 +++- > tools/testing/selftests/ftrace/test.d/ftrace/fgraph-filter.tc | 2 ++ > .../selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc | 3 ++- > .../testing/selftests/ftrace/test.d/ftrace/func-filter-pid.tc | 3 ++- > 4 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-filter-stack.tc b/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-filter-stack.tc > index cf3ea42b12b09f..7e74df1ef928f9 100644 > --- a/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-filter-stack.tc > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-filter-stack.tc > @@ -39,6 +39,7 @@ disable_tracing > clear_trace > enable_tracing > sleep 1 > +disable_tracing > > count=`cat trace | grep '()' | grep -v schedule | wc -l` > > @@ -54,8 +55,9 @@ fi > > echo 0 > /proc/sys/kernel/stack_tracer_enabled > clear_trace > +enable_tracing > sleep 1 > - > +disable_tracing > > count=`cat trace | grep '()' | grep -v schedule | wc -l` > > diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-filter.tc b/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-filter.tc > index b3ccdaec2a61ba..7e65a115054127 100644 > --- a/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-filter.tc > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-filter.tc > @@ -24,6 +24,8 @@ fi > echo function_graph > current_tracer > enable_tracing > sleep 1 > +disable_tracing > + > # search for functions (has "()" on the line), and make sure > # that only the schedule function was found > count=`cat trace | grep '()' | grep -v schedule | wc -l` > diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc > index 80541964b9270b..9fb0511b5d2eeb 100644 > --- a/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-notrace-pid.tc > @@ -51,6 +51,7 @@ do_test() { > > enable_tracing > yield > + disable_tracing > > count_pid=`cat trace | grep -v ^# | grep $PID | wc -l` > count_other=`cat trace | grep -v ^# | grep -v $PID | wc -l` > @@ -60,7 +61,6 @@ do_test() { > fail "PID filtering not working? traced task = $count_pid; other tasks = $count_other " > fi > > - disable_tracing > clear_trace > > if [ $do_function_fork -eq 0 ]; then > @@ -77,6 +77,7 @@ do_test() { > > enable_tracing > yield > + disable_tracing > > count_pid=`cat trace | grep -v ^# | grep $PID | wc -l` > count_other=`cat trace | grep -v ^# | grep -v $PID | wc -l` > diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-pid.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-pid.tc > index 2f7211254529ba..c55bcf2fe1966f 100644 > --- a/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-pid.tc > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func-filter-pid.tc > @@ -51,6 +51,7 @@ do_test() { > > enable_tracing > yield > + disable_tracing > > count_pid=`cat trace | grep -v ^# | grep $PID | wc -l` > count_other=`cat trace | grep -v ^# | grep -v $PID | wc -l` > @@ -60,7 +61,6 @@ do_test() { > fail "PID filtering not working?" > fi > > - disable_tracing > clear_trace > > if [ $do_function_fork -eq 0 ]; then > @@ -72,6 +72,7 @@ do_test() { > > enable_tracing > yield > + disable_tracing > > count_pid=`cat trace | grep -v ^# | grep $PID | wc -l` > count_other=`cat trace | grep -v ^# | grep -v $PID | wc -l` >
-- Masami Hiramatsu (Google) <mhiramat@kernel.org>
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