linux-kernel - Re: [PATCH 8/9] perf test: Free aliases for PMU event map aliases test

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Date:   Mon, 7 Sep 2020 11:28:31 +0100
From:   John Garry <john.garry@...wei.com>
To:     Namhyung Kim <namhyung@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...hat.com>
CC:     Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Stephane Eranian <eranian@...gle.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Andi Kleen <andi@...stfloor.org>,
        Ian Rogers <irogers@...gle.com>
Subject: Re: [PATCH 8/9] perf test: Free aliases for PMU event map aliases
 test

On 07/09/2020 04:45, Namhyung Kim wrote:
> The aliases were never released causing the following leaks:
> 
>    Indirect leak of 1224 byte(s) in 9 object(s) allocated from:
>      #0 0x7feefb830628 in malloc (/lib/x86_64-linux-gnu/libasan.so.5+0x107628)
>      #1 0x56332c8f1b62 in __perf_pmu__new_alias util/pmu.c:322
>      #2 0x56332c8f401f in pmu_add_cpu_aliases_map util/pmu.c:778
>      #3 0x56332c792ce9 in __test__pmu_event_aliases tests/pmu-events.c:295
>      #4 0x56332c792ce9 in test_aliases tests/pmu-events.c:367
>      #5 0x56332c76a09b in run_test tests/builtin-test.c:410
>      #6 0x56332c76a09b in test_and_print tests/builtin-test.c:440
>      #7 0x56332c76ce69 in __cmd_test tests/builtin-test.c:695
>      #8 0x56332c76ce69 in cmd_test tests/builtin-test.c:807
>      #9 0x56332c7d2214 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:312
>      #10 0x56332c6701a8 in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:364
>      #11 0x56332c6701a8 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:408
>      #12 0x56332c6701a8 in main /home/namhyung/project/linux/tools/perf/perf.c:538
>      #13 0x7feefb359cc9 in __libc_start_main ../csu/libc-start.c:308
> 
> Cc: John Garry <john.garry@...wei.com>
> Fixes: 956a78356c24c ("perf test: Test pmu-events aliases")
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
>   tools/perf/tests/pmu-events.c | 5 +++++
>   tools/perf/util/pmu.c         | 2 +-
>   tools/perf/util/pmu.h         | 1 +
>   3 files changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/tests/pmu-events.c b/tools/perf/tests/pmu-events.c
> index eb19f9a0bc15..d3517a74d95e 100644
> --- a/tools/perf/tests/pmu-events.c
> +++ b/tools/perf/tests/pmu-events.c
> @@ -274,6 +274,7 @@ static int __test__pmu_event_aliases(char *pmu_name, int *count)
>   	int res = 0;
>   	bool use_uncore_table;
>   	struct pmu_events_map *map = __test_pmu_get_events_map();
> +	struct perf_pmu_alias *a, *tmp;
>   
>   	if (!map)
>   		return -1;
> @@ -347,6 +348,10 @@ static int __test__pmu_event_aliases(char *pmu_name, int *count)
>   			  pmu_name, alias->name);
>   	}
>   
> +	list_for_each_entry_safe(a, tmp, &aliases, list) {
> +		list_del(&a->list);
> +		perf_pmu_free_alias(a);

This looks ok.

I also notice that we have other paths like this, where the allocated 
pmu (and aliases) are not freed for later error paths, it seems:

parse_events_add_pmu() -> perf_pmu_find() -> pmu_lookup() -> 
pmu_add_cpu_aliases().

I had a quick look at the rest of the series, and could not see if we 
fix up any of this.

Cheers,
john

> +	}
>   	free(pmu);
>   	return res;
>   }
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index f1688e1f6ed7..555cb3524c25 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -274,7 +274,7 @@ static void perf_pmu_update_alias(struct perf_pmu_alias *old,
>   }
>   
>   /* Delete an alias entry. */
> -static void perf_pmu_free_alias(struct perf_pmu_alias *newalias)
> +void perf_pmu_free_alias(struct perf_pmu_alias *newalias)
>   {
>   	zfree(&newalias->name);
>   	zfree(&newalias->desc);
> diff --git a/tools/perf/util/pmu.h b/tools/perf/util/pmu.h
> index 44ccbdbb1c37..b63c4c5e335e 100644
> --- a/tools/perf/util/pmu.h
> +++ b/tools/perf/util/pmu.h
> @@ -113,6 +113,7 @@ void pmu_add_cpu_aliases_map(struct list_head *head, struct perf_pmu *pmu,
>   
>   struct pmu_events_map *perf_pmu__find_map(struct perf_pmu *pmu);
>   bool pmu_uncore_alias_match(const char *pmu_name, const char *name);
> +void perf_pmu_free_alias(struct perf_pmu_alias *alias);
>   
>   int perf_pmu__convert_scale(const char *scale, char **end, double *sval);
>   
>