linux-kernel - Re: [PATCH v2] selftests/ftrace: Use printf for backslash included command

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Date:   Thu, 28 May 2020 10:24:18 -0600
From:   Shuah Khan <skhan@...uxfoundation.org>
To:     Masami Hiramatsu <mhiramat@...nel.org>
Cc:     Shuah Khan <shuah@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org,
        Tom Zanussi <tom.zanussi@...ux.intel.com>,
        Li Philip <philip.li@...el.com>,
        Liu Yiding <yidingx.liu@...el.com>,
        Xiao Yang <yangx.jy@...fujitsu.com>,
        Andreas Schwab <schwab@...ux-m68k.org>,
        David Laight <David.Laight@...LAB.COM>,
        skhan@...uxfoundation.org
Subject: Re: [PATCH v2] selftests/ftrace: Use printf for backslash included
 command

On 5/25/20 3:59 AM, Masami Hiramatsu wrote:
> Hi Shuah,
> 
> Could you pick this to kselftest-next?
> 
> Thank you,
> 
> On Mon, 11 May 2020 22:36:27 +0900
> Masami Hiramatsu <mhiramat@...nel.org> wrote:
> 
>> Since the built-in echo has different behavior in POSIX shell
>> (dash) and bash, kprobe_syntax_errors.tc can fail on dash which
>> interpret backslash escape automatically.
>>
>> To fix this issue, we explicitly use printf "%s" (not interpret
>> backslash escapes) if the command string can include backslash.
>>
>> Reported-by: Liu Yiding <yidingx.liu@...el.com>
>> Suggested-by: Xiao Yang <yangx.jy@...fujitsu.com>
>> Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
>> ---
>>   tools/testing/selftests/ftrace/test.d/functions    |    8 +++++---
>>   .../ftrace/test.d/kprobe/kprobe_syntax_errors.tc   |    4 +++-
>>   2 files changed, 8 insertions(+), 4 deletions(-)
>>
>> diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
>> index 61a3c7e2634d..697c77ef2e2b 100644
>> --- a/tools/testing/selftests/ftrace/test.d/functions
>> +++ b/tools/testing/selftests/ftrace/test.d/functions
>> @@ -119,12 +119,14 @@ yield() {
>>       ping $LOCALHOST -c 1 || sleep .001 || usleep 1 || sleep 1
>>   }
>>   
>> +# Since probe event command may include backslash, explicitly use printf "%s"
>> +# to NOT interpret it.
>>   ftrace_errlog_check() { # err-prefix command-with-error-pos-by-^ command-file
>> -    pos=$(echo -n "${2%^*}" | wc -c) # error position
>> -    command=$(echo "$2" | tr -d ^)
>> +    pos=$(printf "%s" "${2%^*}" | wc -c) # error position
>> +    command=$(printf "%s" "$2" | tr -d ^)
>>       echo "Test command: $command"
>>       echo > error_log
>> -    (! echo "$command" >> "$3" ) 2> /dev/null
>> +    (! printf "%s" "$command" >> "$3" ) 2> /dev/null
>>       grep "$1: error:" -A 3 error_log
>>       N=$(tail -n 1 error_log | wc -c)
>>       # "  Command: " and "^\n" => 13
>> diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
>> index ef1e9bafb098..eb0f4ab4e070 100644
>> --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
>> +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc
>> @@ -91,7 +91,9 @@ esac
>>   if grep -q "Create/append/" README && grep -q "imm-value" README; then
>>   echo 'p:kprobes/testevent _do_fork' > kprobe_events
>>   check_error '^r:kprobes/testevent do_exit'	# DIFF_PROBE_TYPE
>> -echo 'p:kprobes/testevent _do_fork abcd=\1' > kprobe_events
>> +
>> +# Explicitly use printf "%s" to not interpret \1
>> +printf "%s" 'p:kprobes/testevent _do_fork abcd=\1' > kprobe_events
>>   check_error 'p:kprobes/testevent _do_fork ^bcd=\1'	# DIFF_ARG_TYPE
>>   check_error 'p:kprobes/testevent _do_fork ^abcd=\1:u8'	# DIFF_ARG_TYPE
>>   check_error 'p:kprobes/testevent _do_fork ^abcd=\"foo"'	# DIFF_ARG_TYPE
>>
> 
> 

Applied to

git.kernel.org/pub/scm/linux/kernel/git/shuah/linux kselftest.git/ next
branch for Linux 5.8-rc1

thanks,
-- Shuah