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Message-ID: <ZfsBopALY3whsst5@x1>
Date: Wed, 20 Mar 2024 12:32:50 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ian Rogers <irogers@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Namhyung Kim <namhyung@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] perf: Suggest inbuilt commands for unknown command
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@...lbox 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@...lbox perf-tools-next]$ perf raccord
> Fatal: Out of memory, realloc failed
> ⬢[acme@...lbox 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@...lbox perf-tools-next]$ perf raccord
> Fatal: Out of memory, realloc failed
> ⬢[acme@...lbox 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@...lbox 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@...lbox perf-tools-next]$ perf raccord
perf: 'raccord' is not a perf-command. See 'perf --help'.
⬢[acme@...lbox perf-tools-next]$
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