Re: [PATCH 02/16] perf pmu: Let pmu's with no events show up on perf list

From: Arnaldo Carvalho de Melo
Date: Fri Oct 24 2014 - 09:21:53 EST


Em Fri, Oct 24, 2014 at 10:03:20AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Fri, Oct 24, 2014 at 09:57:02AM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Fri, Oct 24, 2014 at 02:15:52PM +0900, Namhyung Kim escreveu:
> > > On Thu, 23 Oct 2014 13:45:10 +0300, Adrian Hunter wrote:
> > > > + if (pmu->selectable) {
> > > > + scnprintf(buf, sizeof(buf), "%s//", pmu->name);
> > > > + aliases[j] = strdup(buf);
> > >
> > > You need to check the return value here (and above too).
> >
> > Well spotted, fixing this up.
>
> Oh well, this print_pmu_events() function needs some care, it starts by
> trying to alloc the array, if it fails, it silently returns, does that
> mean that there are no pmu events? Or that memory allocation failed?
>
> Ok, will do the fixes in a separate patch...
>
> - Arnaldo

The patch below should check everything and warn the user, even
maintaining that void return...

Acked-by tags welcome as always :-)

- Arnaldo


diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 91dca60..881b754 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -753,9 +753,9 @@ void print_pmu_events(const char *event_glob, bool name_only)
if (pmu->selectable)
len++;
}
- aliases = malloc(sizeof(char *) * len);
+ aliases = zalloc(sizeof(char *) * len);
if (!aliases)
- return;
+ goto out_enomem;
pmu = NULL;
j = 0;
while ((pmu = perf_pmu__scan(pmu)) != NULL) {
@@ -768,16 +768,20 @@ void print_pmu_events(const char *event_glob, bool name_only)
(!is_cpu && strglobmatch(alias->name,
event_glob))))
continue;
- aliases[j] = name;
+
if (is_cpu && !name_only)
- aliases[j] = format_alias_or(buf, sizeof(buf),
- pmu, alias);
- aliases[j] = strdup(aliases[j]);
+ name = format_alias_or(buf, sizeof(buf), pmu, alias);
+
+ aliases[j] = strdup(name);
+ if (aliases[j] == NULL)
+ goto out_enomem;
j++;
}
if (pmu->selectable) {
- scnprintf(buf, sizeof(buf), "%s//", pmu->name);
- aliases[j] = strdup(buf);
+ char *s;
+ if (asprintf(&s, "%s//", pmu->name) < 0)
+ goto out_enomem;
+ aliases[j] = s;
j++;
}
}
@@ -789,12 +793,20 @@ void print_pmu_events(const char *event_glob, bool name_only)
continue;
}
printf(" %-50s [Kernel PMU event]\n", aliases[j]);
- zfree(&aliases[j]);
printed++;
}
if (printed)
printf("\n");
- free(aliases);
+out_free:
+ for (j = 0; j < len; j++)
+ zfree(&aliases[j]);
+ zfree(&aliases);
+ return;
+
+out_enomem:
+ printf("FATAL: not enough memory to print PMU events\n");
+ if (aliases)
+ goto out_free;
}

bool pmu_have_event(const char *pname, const char *name)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/