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Date: Wed, 20 Mar 2024 12:41:42 -0300
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@redhat.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] perf: Suggest inbuilt commands for unknown command
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On Wed, Mar 20, 2024 at 12:32:50PM -0300, Arnaldo Carvalho de Melo wrote:
> On Wed, Mar 20, 2024 at 12:20:20PM -0300, Arnaldo Carvalho de Melo wrote:
> > On Wed, Mar 20, 2024 at 08:12:56AM -0700, Ian Rogers wrote:
> > > Ah, the change:
> > > 
> > > -               static int done_help;
> > > +               int done_help;
> > > 
> > > created an uninitialized use. Compiler warning/sanitizers? Anyway,
> > > done_help needs hoisting out of the loop and initializing to zero, or
> > > being made static again (ugh).
> > 
> > ⬢[acme@toolbox perf-tools-next]$ git diff
> > diff --git a/tools/perf/perf.c b/tools/perf/perf.c
> > index c719e6ccd9e27778..f9532b20e87cbf05 100644
> > --- a/tools/perf/perf.c
> > +++ b/tools/perf/perf.c
> > @@ -459,7 +459,7 @@ static int libperf_print(enum libperf_print_level level,
> >  
> >  int main(int argc, const char **argv)
> >  {
> > -       int err;
> > +       int err, done_help = 0;
> >         const char *cmd;
> >         char sbuf[STRERR_BUFSIZE];
> >  
> > @@ -558,8 +558,6 @@ int main(int argc, const char **argv)
> >         pthread__block_sigwinch();
> >  
> >         while (1) {
> > -               int done_help;
> > -
> >                 run_argv(&argc, &argv);
> >  
> >                 if (errno != ENOENT)
> > ⬢[acme@toolbox perf-tools-next]$ perf raccord
> >   Fatal: Out of memory, realloc failed
> > ⬢[acme@toolbox perf-tools-next]$
> > 
> > Then:
> > 
> > diff --git a/tools/perf/perf.c b/tools/perf/perf.c
> > index c719e6ccd9e27778..54f62aa6612bc290 100644
> > --- a/tools/perf/perf.c
> > +++ b/tools/perf/perf.c
> > @@ -558,7 +558,7 @@ int main(int argc, const char **argv)
> >         pthread__block_sigwinch();
> >  
> >         while (1) {
> > -               int done_help;
> > +               static int done_help;
> >  
> >                 run_argv(&argc, &argv);
> >  
> > ⬢[acme@toolbox perf-tools-next]$ perf raccord
> >   Fatal: Out of memory, realloc failed
> > ⬢[acme@toolbox perf-tools-next]$
> 
> That main_cmds variable is uninitialized, which ends up making
> add_cmdname() to explode, are you sure this is working on your side?
> 
> Further clarifying, this is without considering the second patch, I
> haven't got to it yet, from what I recall from the description it
> shouldn't matter tho.
> 
> - Arnaldo
> 
> ⬢[acme@toolbox perf-tools-next]$ git diff
> diff --git a/tools/perf/perf.c b/tools/perf/perf.c
> index c719e6ccd9e27778..164b3c78baff4204 100644
> --- a/tools/perf/perf.c
> +++ b/tools/perf/perf.c
> @@ -558,7 +558,7 @@ int main(int argc, const char **argv)
>         pthread__block_sigwinch();
>  
>         while (1) {
> -               int done_help;
> +               static int done_help;
>  
>                 run_argv(&argc, &argv);
>  
> @@ -566,7 +566,7 @@ int main(int argc, const char **argv)
>                         break;
>  
>                 if (!done_help) {
> -                       struct cmdnames main_cmds;
> +                       struct cmdnames main_cmds = { 0, };
>  
>                         for (unsigned int i = 0; i < ARRAY_SIZE(commands); i++) {
>                                 add_cmdname(&main_cmds,
> ⬢[acme@toolbox perf-tools-next]$ perf raccord
> perf: 'raccord' is not a perf-command. See 'perf --help'.
> ⬢[acme@toolbox perf-tools-next]$ 

But:

⬢[acme@toolbox perf-tools-next]$ perf raccord
perf: 'raccord' is not a perf-command. See 'perf --help'.
⬢[acme@toolbox perf-tools-next]$ perf ricord
perf: 'ricord' is not a perf-command. See 'perf --help'.

Did you mean this?
	record
⬢[acme@toolbox perf-tools-next]$ perf ricord
perf: 'ricord' is not a perf-command. See 'perf --help'.

Did you mean this?
	record
⬢[acme@toolbox perf-tools-next]$

So I'll add that and go on from there.

- Arnaldo