Re: [PATCH] perf map: fix infinite loop on map_groups__fixup_overlappings

From: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
To: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Matheus Marchini <mmarchini@netflix.com>,
	linux-perf-users@vger.kernel.org, jkoch@netflix.com,
	khlebnikov@yandex-team.ru, Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Changbin Du <changbin.du@intel.com>,
	Song Liu <songliubraving@fb.com>,
	John Keeping <john@metanate.com>, Andi Kleen <ak@linux.intel.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf map: fix infinite loop on map_groups__fixup_overlappings
Date: Wed, 11 Dec 2019 15:13:13 -0300	[thread overview]
Message-ID: <20191211181313.GE13965@kernel.org> (raw)
In-Reply-To: <20191211160734.18087-1-mmarchini@netflix.com>

Em Wed, Dec 11, 2019 at 08:07:31AM -0800, Matheus Marchini escreveu:
> In some cases, when using perf inject and there are JIT_CODE_MOVE
> records in the jitdump file, perf will end up in an infinite loop on
> map_groups__fixup_overlappings, which will keep allocating memory
> indefinitely. This issue was observed on Node.js (with changes to
> generate JIT_CODE_MOVE records) and on Java.
> 
> This issue started to occur after 6a9405b56c274 (perf map:
> Optimize maps__fixup_overlappings()). To prevent it from happening,
> partially revert those changes without losing the optimizations
> introduced in it.

Konstantin, can you please take a look and provide your Acked-by or
Reviewed-by?

- Arnaldo

> Signed-off-by: Matheus Marchini <mmarchini@netflix.com>
> ---
>  tools/perf/util/map.c | 17 +++++++++++++++++
>  tools/perf/util/map.h |  1 +
>  2 files changed, 18 insertions(+)
> 
> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> index 744bfbaf35cf..8918fdb8ddab 100644
> --- a/tools/perf/util/map.c
> +++ b/tools/perf/util/map.c
> @@ -781,6 +781,21 @@ static void __map_groups__insert(struct map_groups *mg, struct map *map)
>  	__maps__insert(&mg->maps, map);
>  }
>  
> +int map__overlap(struct map *l, struct map *r)
> +{
> +	if (l->start > r->start) {
> +		struct map *t = l;
> +
> +		l = r;
> +		r = t;
> +	}
> +
> +	if (l->end > r->start)
> +		return 1;
> +
> +	return 0;
> +}
> +
>  int map_groups__fixup_overlappings(struct map_groups *mg, struct map *map, FILE *fp)
>  {
>  	struct maps *maps = &mg->maps;
> @@ -821,6 +836,8 @@ int map_groups__fixup_overlappings(struct map_groups *mg, struct map *map, FILE
>  		 */
>  		if (pos->start >= map->end)
>  			break;
> +		if (!map__overlap(map, pos))
> +			continue;
>  
>  		if (verbose >= 2) {
>  
> diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
> index 5e8899883231..1383571437aa 100644
> --- a/tools/perf/util/map.h
> +++ b/tools/perf/util/map.h
> @@ -132,6 +132,7 @@ static inline void __map__zput(struct map **map)
>  
>  #define map__zput(map) __map__zput(&map)
>  
> +int map__overlap(struct map *l, struct map *r);
>  size_t map__fprintf(struct map *map, FILE *fp);
>  size_t map__fprintf_dsoname(struct map *map, FILE *fp);
>  char *map__srcline(struct map *map, u64 addr, struct symbol *sym);
> -- 
> 2.17.1

-- 

- Arnaldo