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Commit ec09a42a authored by Elena Reshetova's avatar Elena Reshetova Committed by Arnaldo Carvalho de Melo
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perf cpumap: Convert cpu_map.refcnt from atomic_t to refcount_t 



The refcount_t type and corresponding API should be used instead of atomic_t
when the variable is used as a reference counter.

This allows to avoid accidental refcounter overflows that might lead to
use-after-free situations.

Signed-off-by: default avatarElena Reshetova <elena.reshetova@intel.com>
Signed-off-by: default avatarDavid Windsor <dwindsor@gmail.com>
Signed-off-by: default avatarHans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: default avatarKees Kook <keescook@chromium.org>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kees Kook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: alsa-devel@alsa-project.org
Link: http://lkml.kernel.org/r/1487691303-31858-3-git-send-email-elena.reshetova@intel.com


[ fixed mixed conversion to refcount in tests/cpumap.c ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 79c5fe6d

tools/perf/tests/cpumap.c

+1 −1
Original line number Diff line number Diff line
@@ -66,7 +66,7 @@ static int process_event_cpus(struct perf_tool *tool __maybe_unused, 
	TEST_ASSERT_VAL("wrong nr",  map->nr == 2);

	TEST_ASSERT_VAL("wrong cpu", map->map[0] == 1);

	TEST_ASSERT_VAL("wrong cpu", map->map[1] == 256);

	TEST_ASSERT_VAL("wrong refcnt", atomic_read(&map->refcnt) == 1);

	TEST_ASSERT_VAL("wrong refcnt", refcount_read(&map->refcnt) == 1);

	cpu_map__put(map);

	return 0;

}

tools/perf/util/cpumap.c

+8 −8
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ static struct cpu_map *cpu_map__default_new(void) 
			cpus->map[i] = i;



		cpus->nr = nr_cpus;

		atomic_set(&cpus->refcnt, 1);

		refcount_set(&cpus->refcnt, 1);

	}



	return cpus;
@@ -43,7 +43,7 @@ static struct cpu_map *cpu_map__trim_new(int nr_cpus, int *tmp_cpus) 
	if (cpus != NULL) {

		cpus->nr = nr_cpus;

		memcpy(cpus->map, tmp_cpus, payload_size);

		atomic_set(&cpus->refcnt, 1);

		refcount_set(&cpus->refcnt, 1);

	}



	return cpus;
@@ -252,7 +252,7 @@ struct cpu_map *cpu_map__dummy_new(void) 
	if (cpus != NULL) {

		cpus->nr = 1;

		cpus->map[0] = -1;

		atomic_set(&cpus->refcnt, 1);

		refcount_set(&cpus->refcnt, 1);

	}



	return cpus;
@@ -269,7 +269,7 @@ struct cpu_map *cpu_map__empty_new(int nr) 
		for (i = 0; i < nr; i++)

			cpus->map[i] = -1;



		atomic_set(&cpus->refcnt, 1);

		refcount_set(&cpus->refcnt, 1);

	}



	return cpus;
@@ -278,7 +278,7 @@ struct cpu_map *cpu_map__empty_new(int nr) 
static void cpu_map__delete(struct cpu_map *map)

{

	if (map) {

		WARN_ONCE(atomic_read(&map->refcnt) != 0,

		WARN_ONCE(refcount_read(&map->refcnt) != 0,

			  "cpu_map refcnt unbalanced\n");

		free(map);

	}
@@ -287,13 +287,13 @@ static void cpu_map__delete(struct cpu_map *map) 
struct cpu_map *cpu_map__get(struct cpu_map *map)

{

	if (map)

		atomic_inc(&map->refcnt);

		refcount_inc(&map->refcnt);

	return map;

}



void cpu_map__put(struct cpu_map *map)

{

	if (map && atomic_dec_and_test(&map->refcnt))

	if (map && refcount_dec_and_test(&map->refcnt))

		cpu_map__delete(map);

}
@@ -357,7 +357,7 @@ int cpu_map__build_map(struct cpu_map *cpus, struct cpu_map **res, 
	/* ensure we process id in increasing order */

	qsort(c->map, c->nr, sizeof(int), cmp_ids);



	atomic_set(&c->refcnt, 1);

	refcount_set(&c->refcnt, 1);

	*res = c;

	return 0;

}

tools/perf/util/cpumap.h

+2 −2
Original line number Diff line number Diff line
@@ -3,13 +3,13 @@ 


#include <stdio.h>

#include <stdbool.h>

#include <linux/atomic.h>

#include <linux/refcount.h>



#include "perf.h"

#include "util/debug.h"



struct cpu_map {

	atomic_t refcnt;

	refcount_t refcnt;

	int nr;

	int map[];

};