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Message-ID: <1ee16ad1-925a-411d-c67e-5ddab2fb6074@sangfor.com.cn>
Date:   Thu, 6 Apr 2023 18:35:50 +0800
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Subject: Re: [PATCH v10 8/8] selftests/ftrace: Add funcgraph-retval test case
From:   Donglin Peng <pengdonglin@sangfor.com.cn>
To:     "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc:     rostedt@goodmis.org, linux@armlinux.org.uk, mark.rutland@arm.com,
        will@kernel.org, catalin.marinas@arm.com,
        rmk+kernel@armlinux.org.uk, palmer@dabbelt.com,
        paul.walmsley@sifive.com, aou@eecs.berkeley.edu,
        tglx@linutronix.de, dave.hansen@linux.intel.com, x86@kernel.org,
        bp@alien8.de, hpa@zytor.com, chenhuacai@kernel.org,
        zhangqing@loongson.cn, kernel@xen0n.name, mingo@redhat.com,
        peterz@infradead.org, xiehuan09@gmail.com, dinghui@sangfor.com.cn,
        huangcun@sangfor.com.cn, dolinux.peng@gmail.com,
        linux-trace-kernel@vger.kernel.org, loongarch@lists.linux.dev,
        linux-riscv@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
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On 2023/4/3 13:01, Donglin Peng wrote:
> On 2023/4/3 10:33, Donglin Peng wrote:
>> On 2023/4/2 6:04, Masami Hiramatsu (Google) wrote:
>>> On Fri, 31 Mar 2023 05:47:44 -0700
>>> Donglin Peng <pengdonglin@sangfor.com.cn> wrote:
>>>
>>>> Add a test case for the funcgraph-retval and funcgraph-retval-hex
>>>> trace options.
>>>>
>>>> Signed-off-by: Donglin Peng <pengdonglin@sangfor.com.cn>
>>>> ---
>>>> 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 "$$" for self pid.
>>
>> Yeah, I will fix it.
> 
> I found that ftracetest used () to launch a new child process for
> executing a .tc script file, however the $$ value remains unchanged,
> so we can not use $$ here, because it is PPID. Therefore I think we
> have to get PID from /proc/self/stat.
> 
> Here is the code from ftracetest that launches a child shell for 
> executing the .tc file.
> 
> __run_test() { # testfile
>    # setup PID and PPID, $$ is *not* updated.
>    (cd $TRACING_DIR; read PID _ < /proc/self/stat; set -e; set -x;
>     checkreq $1; initialize_ftrace; . $1)
>    [ $? -ne 0 ] && kill -s $SIG_FAIL $SIG_PID
> }
> 
>>
>>>
>>>> +[ -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
>>>>
>>>
>>>
>>
> 

Hi Masami,

I will update the selftest as follows, according to the comments:

#!/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

# get self PID, can not use $$, because it is PPID
read PID _ < /proc/self/stat

[ -f set_ftrace_filter ] && echo proc_reg_write > set_ftrace_filter
[ -f set_ftrace_pid ] && echo ${PID} > set_ftrace_pid
echo function_graph > current_tracer
echo 1 > options/funcgraph-retval

set +e
enable_tracing
echo > /proc/interrupts
disable_tracing
set -e

: "Test printing the error code in signed decimal format"
echo 0 > options/funcgraph-retval-hex
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 1 > options/funcgraph-retval-hex
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