Re: [PATCH v10 8/8] selftests/ftrace: Add funcgraph-retval test case

[Donglin Peng]

On 2023/4/2 6:04, Masami Hiramatsu (Google) wrote:
> On Fri, 31 Mar 2023 05:47:44 -0700
> Donglin Peng <pengdonglin@xxxxxxxxxxxxxx> wrote:
>
> > Add a test case for the funcgraph-retval and funcgraph-retval-hex
> > trace options.
> >
> > Signed-off-by: Donglin Peng <pengdonglin@xxxxxxxxxxxxxx>
> > ---
> > v10:
> >   - Fix issues in selftest
> >
> > v8:
> >   - Fix issues in selftest
> > ---
> >   .../ftrace/test.d/ftrace/fgraph-retval.tc     | 43 +++++++++++++++++++
> >   1 file changed, 43 insertions(+)
> >   create mode 100644 tools/testing/selftests/ftrace/test.d/ftrace/fgraph-retval.tc
> >
> > diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-retval.tc b/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-retval.tc
> > new file mode 100644
> > index 000000000000..5819aa2dd6ad
> > --- /dev/null
> > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/fgraph-retval.tc
> > @@ -0,0 +1,43 @@
> > +#!/bin/sh
> > +# SPDX-License-Identifier: GPL-2.0
> > +# description: ftrace - function graph print function return value
> > +# requires: options/funcgraph-retval options/funcgraph-retval-hex function_graph:tracer
> > +
> > +# Make sure that funcgraph-retval works
> > +
> > +fail() { # msg
> > +    echo $1
> > +    exit_fail
> > +}
> > +
> > +disable_tracing
> > +clear_trace
> > +
> > +read PID _ < /proc/self/stat
>
> You can use "$$" for self pid.

Yeah, I will fix it.

> > +[ -f set_ftrace_pid ] && echo ${PID} > set_ftrace_pid
> > +[ -f set_ftrace_filter ] && echo proc_reg_write > set_ftrace_filter
> > +[ -f set_graph_function ] && echo proc_reg_write > set_graph_function
>
> You should set the required files for this test, so that the test result
> is always same. BTW, you need to set either 'set_ftrace_filter' or
> 'set_graph_function'.

Yes, but I discovered that set_ftrace_filter and set_graph_function rely 
on the CONFIG_DYNAMIC_FTRACE configuration, which means that these two 
files are not present when CONFIG_DYNAMIC_FTRACE is disabled, even if 
CONFIG_FUNCTION_GRAPH_RETVAL is enabled. Therefore, I think that these 
two trace files are not necessary for this test.

I will modify the above like this:

[ -f set_ftrace_pid ] && echo $$ > set_ftrace_pid
[ -f set_ftrace_filter ] && echo proc_reg_write > set_ftrace_filter

> > +echo function_graph > current_tracer
> > +echo funcgraph-retval > trace_options
> > +
> > +set +e
> > +enable_tracing
> > +echo > /proc/interrupts
> > +disable_tracing
> > +set -e
> > +
> > +: "Test printing the error code in signed decimal format"
> > +echo nofuncgraph-retval-hex > trace_options
>
> echo 0 > options/funcgraph-retval-hex
>
> If you require 'options/funcgraph-retval-hex' file, you can use the
> file to set it or clear it.

Yeah.

> > +count=`cat trace | grep 'proc_reg_write' | grep '= -5' | wc -l`
> > +if [ $count -eq 0 ]; then
> > +    fail "Return value can not be printed in signed decimal format"
> > +fi
> > +
> > +: "Test printing the error code in hexadecimal format"
> > +echo funcgraph-retval-hex > trace_options
>
> Ditto.

Thanks.

> Thanks,
>
> > +count=`cat trace | grep 'proc_reg_write' | grep 'fffffffb' | wc -l`
> > +if [ $count -eq 0 ]; then
> > +    fail "Return value can not be printed in hexadecimal format"
> > +fi
> > +
> > +exit 0
> > --
> > 2.25.1