linux-kernel - Re: [PATCH 3/3] selftests/ftrace: Use /bin/echo instead of built-in echo

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Message-Id: <20200507181505.3e8369ee39f14d9c74ec986b@kernel.org>
Date:   Thu, 7 May 2020 18:15:05 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Xiao Yang <yangx.jy@...fujitsu.com>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        Shuah Khan <shuah@...nel.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>
Subject: Re: [PATCH 3/3] selftests/ftrace: Use /bin/echo instead of built-in
 echo

On Thu, 7 May 2020 14:45:16 +0800
Xiao Yang <yangx.jy@...fujitsu.com> wrote:

> On 2020/5/1 21:38, Masami Hiramatsu wrote:
> > Since the built-in echo has different behavior in POSIX shell
> > (dash) and bash, we forcibly use /bin/echo -E (not interpret
> > backslash escapes) by default.
> >
> > This also fixes some test cases which expects built-in
> > echo command.
> >
> > Reported-by: Liu Yiding<yidingx.liu@...el.com>
> > Signed-off-by: Masami Hiramatsu<mhiramat@...nel.org>
> > ---
> >   tools/testing/selftests/ftrace/test.d/functions    |    3 +++
> >   .../test.d/trigger/trigger-trace-marker-hist.tc    |    2 +-
> >   .../trigger-trace-marker-synthetic-kernel.tc       |    4 ++++
> >   .../trigger/trigger-trace-marker-synthetic.tc      |    4 ++--
> >   4 files changed, 10 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
> > index 5d4550591ff9..ea59b6ea2c3e 100644
> > --- a/tools/testing/selftests/ftrace/test.d/functions
> > +++ b/tools/testing/selftests/ftrace/test.d/functions
> > @@ -1,3 +1,6 @@
> > +# Since the built-in echo has different behavior in POSIX shell (dash) and
> > +# bash, we forcibly use /bin/echo -E (not interpret backslash escapes).
> > +alias echo="/bin/echo -E"
> Hi Masami, Steven
> 
> It seems that only kprobe_syntax_errors.tc is impacted by the issue 
> currently.  Is it necessary for all tests to use /bin/echo and could we 
> just make kprobe_syntax_errors.tc use /bin/echo?

Yes, I would like to unify the "echo"'s behavior among the testcases
instead of patching each failure in the future.
Or would you have any concern on it?

Thank you,

> 
> Best Regards,
> Xiao Yang
> 
> >
> >   clear_trace() { # reset trace output
> >       echo>  trace
> > diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-hist.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-hist.tc
> > index ab6bedb25736..b3f70f53ee69 100644
> > --- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-hist.tc
> > +++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-hist.tc
> > @@ -30,7 +30,7 @@ fi
> >
> >   echo "Test histogram trace_marker tigger"
> >
> > -echo 'hist:keys=common_pid'>  events/ftrace/print/trigger
> > +echo 'hist:keys=ip'>  events/ftrace/print/trigger
> >   for i in `seq 1 10` ; do echo "hello">  trace_marker; done
> >   grep 'hitcount: *10$' events/ftrace/print/hist>  /dev/null || \
> >       fail "hist trigger did not trigger correct times on trace_marker"
> > diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic-kernel.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic-kernel.tc
> > index 18b4d1c2807e..c1625d945f4d 100644
> > --- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic-kernel.tc
> > +++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic-kernel.tc
> > @@ -44,6 +44,10 @@ echo 'latency u64 lat'>  synthetic_events
> >   echo 'hist:keys=pid:ts0=common_timestamp.usecs'>  events/sched/sched_waking/trigger
> >   echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).latency($lat)'>  events/ftrace/print/trigger
> >   echo 'hist:keys=common_pid,lat:sort=lat'>  events/synthetic/latency/trigger
> > +
> > +# We have to use the built-in echo here because waking up pid must be same
> > +# as echoing pid.
> > +alias echo=echo
> >   sleep 1
> >   echo "hello">  trace_marker
> >
> > diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
> > index dd262d6d0db6..23e52c8d71de 100644
> > --- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
> > +++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-trace-marker-synthetic.tc
> > @@ -36,8 +36,8 @@ fi
> >   echo "Test histogram trace_marker to trace_marker latency histogram trigger"
> >
> >   echo 'latency u64 lat'>  synthetic_events
> > -echo 'hist:keys=common_pid:ts0=common_timestamp.usecs if buf == "start"'>  events/ftrace/print/trigger
> > -echo 'hist:keys=common_pid:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat) if buf == "end"'>>  events/ftrace/print/trigger
> > +echo 'hist:keys=ip:ts0=common_timestamp.usecs if buf == "start"'>  events/ftrace/print/trigger
> > +echo 'hist:keys=ip:lat=common_timestamp.usecs-$ts0:onmatch(ftrace.print).latency($lat) if buf == "end"'>>  events/ftrace/print/trigger
> >   echo 'hist:keys=common_pid,lat:sort=lat'>  events/synthetic/latency/trigger
> >   echo -n "start">  trace_marker
> >   echo -n "end">  trace_marker
> >
> >
> >
> > .
> >
> 
> 
> 


-- 
Masami Hiramatsu <mhiramat@...nel.org>