On Fri, 24 Aug 2018 19:23:52 -0400 Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > On Fri, 17 Aug 2018 01:40:30 +0900 > Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote: > > > Add a testcase for max stack tracer, which checks basic > > max stack usage tracing and its filter feature. > > > > Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> > > --- > > .../ftrace/test.d/ftrace/func_stack_tracer.tc | 39 ++++++++++++++++++++ > > 1 file changed, 39 insertions(+) > > create mode 100644 tools/testing/selftests/ftrace/test.d/ftrace/func_stack_tracer.tc > > > > diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_stack_tracer.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_stack_tracer.tc > > new file mode 100644 > > index 000000000000..b414f0e3c646 > > --- /dev/null > > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_stack_tracer.tc > > @@ -0,0 +1,39 @@ > > +#!/bin/sh > > +# SPDX-License-Identifier: GPL-2.0 > > +# description: ftrace - Max stack tracer > > +# Test the basic function of max-stack usage tracing > > + > > +if [ ! -f stack_trace ]; then > > + echo "Max stack tracer is not supported - please make CONFIG_STACK_TRACER=y" > > + exit_unsupported > > +fi > > + > > +echo > stack_trace_filter > > +echo 0 > stack_max_size > > +echo 1 > /proc/sys/kernel/stack_tracer_enabled > > + > > +: "Fork and wait for the first entry become !lock" > > +timeout=10 > > +while [ $timeout -ne 0 ]; do > > + ( echo "forked" ) > > + FL=`grep " 0)" stack_trace` > > + echo $FL | grep -q "lock" || break; > > + timeout=$((timeout - 1)) > > +done > > +echo 0 > /proc/sys/kernel/stack_tracer_enabled > > + > > +echo '*lock*' > stack_trace_filter > > +test `cat stack_trace_filter | wc -l` -eq `grep lock stack_trace_filter | wc -l` > > + > > +echo 0 > stack_max_size > > +echo 1 > /proc/sys/kernel/stack_tracer_enabled > > This test fails quite a bit because it doesn't guarantee that another > stack trace gets in that is bigger, and we don't find the "lock". Hmm, maybe I misunderstand what is the stack_trace_filter. I thought it filtered the function that triggered stack trace, so the top of stack trace was always filtered function. If not, what does this filter? Thank you, > > -- Steve > > > + > > +: "Fork and always the first entry including lock" > > +timeout=10 > > +while [ $timeout -ne 0 ]; do > > + ( echo "forked" ) > > + FL=`grep " 0)" stack_trace` > > + echo $FL | grep -q "lock" > > + timeout=$((timeout - 1)) > > +done > > +echo 0 > /proc/sys/kernel/stack_tracer_enabled > -- Masami Hiramatsu <mhiramat@xxxxxxxxxx>
