Commit da885a0e authored by Ian Rogers's avatar Ian Rogers Committed by Arnaldo Carvalho de Melo
Browse files

perf cpumap: Add reference count checking 

Enabled when REFCNT_CHECKING is defined. The change adds a memory
allocated pointer that is interposed between the reference counted cpu
map at a get and freed by a put. The pointer replaces the original
perf_cpu_map struct, so use of the perf_cpu_map via APIs remains
unchanged. Any use of the cpu map without the API requires two versions,
handled via the RC_CHK_ACCESS macro.

This change is intended to catch:

 - use after put: using a cpumap after you have put it will cause a
   segv.
 - unbalanced puts: two puts for a get will result in a double free
   that can be captured and reported by tools like address sanitizer,
   including with the associated stack traces of allocation and frees.
 - missing puts: if a put is missing then the get turns into a memory
   leak that can be reported by leak sanitizer, including the stack
   trace at the point the get occurs.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Hao Luo <haoluo@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Miaoqian Lin <linmq006@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Shunsuke Nakamura <nakamura.shun@fujitsu.com>
Cc: Song Liu <song@kernel.org>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>,
Cc: Yury Norov <yury.norov@gmail.com>
Link: https://lore.kernel.org/lkml/20230407230405.2931830-3-irogers@google.com


[ Extracted from a larger patch ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 491b13c4

tools/lib/perf/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -188,7 +188,7 @@ install_lib: libs 
		cp -fpR $(LIBPERF_ALL) $(DESTDIR)$(libdir_SQ)



HDRS := bpf_perf.h core.h cpumap.h threadmap.h evlist.h evsel.h event.h mmap.h

INTERNAL_HDRS := cpumap.h evlist.h evsel.h lib.h mmap.h threadmap.h xyarray.h

INTERNAL_HDRS := cpumap.h evlist.h evsel.h lib.h mmap.h rc_check.h threadmap.h xyarray.h



INSTALL_HDRS_PFX := $(DESTDIR)$(prefix)/include/perf

INSTALL_HDRS := $(addprefix $(INSTALL_HDRS_PFX)/, $(HDRS))

tools/lib/perf/cpumap.c

+46 −39
Original line number Diff line number Diff line
@@ -12,19 +12,19 @@ 


void perf_cpu_map__set_nr(struct perf_cpu_map *map, int nr_cpus)

{

	map->nr = nr_cpus;

	RC_CHK_ACCESS(map)->nr = nr_cpus;

}



struct perf_cpu_map *perf_cpu_map__alloc(int nr_cpus)

{

	struct perf_cpu_map *cpus = malloc(sizeof(*cpus) + sizeof(struct perf_cpu) * nr_cpus);

	RC_STRUCT(perf_cpu_map) *cpus = malloc(sizeof(*cpus) + sizeof(struct perf_cpu) * nr_cpus);

	struct perf_cpu_map *result;



	if (cpus != NULL) {

	if (ADD_RC_CHK(result, cpus)) {

		cpus->nr = nr_cpus;

		refcount_set(&cpus->refcnt, 1);



	}

	return cpus;

	return result;

}



struct perf_cpu_map *perf_cpu_map__dummy_new(void)
@@ -32,7 +32,7 @@ struct perf_cpu_map *perf_cpu_map__dummy_new(void) 
	struct perf_cpu_map *cpus = perf_cpu_map__alloc(1);



	if (cpus)

		cpus->map[0].cpu = -1;

		RC_CHK_ACCESS(cpus)->map[0].cpu = -1;



	return cpus;

}
@@ -42,21 +42,28 @@ static void cpu_map__delete(struct perf_cpu_map *map) 
	if (map) {

		WARN_ONCE(refcount_read(perf_cpu_map__refcnt(map)) != 0,

			  "cpu_map refcnt unbalanced\n");

		free(map);

		RC_CHK_FREE(map);

	}

}



struct perf_cpu_map *perf_cpu_map__get(struct perf_cpu_map *map)

{

	if (map)

	struct perf_cpu_map *result;



	if (RC_CHK_GET(result, map))

		refcount_inc(perf_cpu_map__refcnt(map));

	return map;



	return result;

}



void perf_cpu_map__put(struct perf_cpu_map *map)

{

	if (map && refcount_dec_and_test(perf_cpu_map__refcnt(map)))

	if (map) {

		if (refcount_dec_and_test(perf_cpu_map__refcnt(map)))

			cpu_map__delete(map);

		else

			RC_CHK_PUT(map);

	}

}



static struct perf_cpu_map *cpu_map__default_new(void)
@@ -73,7 +80,7 @@ static struct perf_cpu_map *cpu_map__default_new(void) 
		int i;



		for (i = 0; i < nr_cpus; ++i)

			cpus->map[i].cpu = i;

			RC_CHK_ACCESS(cpus)->map[i].cpu = i;

	}



	return cpus;
@@ -99,15 +106,15 @@ static struct perf_cpu_map *cpu_map__trim_new(int nr_cpus, const struct perf_cpu 
	int i, j;



	if (cpus != NULL) {

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

		qsort(cpus->map, nr_cpus, sizeof(struct perf_cpu), cmp_cpu);

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

		qsort(RC_CHK_ACCESS(cpus)->map, nr_cpus, sizeof(struct perf_cpu), cmp_cpu);

		/* Remove dups */

		j = 0;

		for (i = 0; i < nr_cpus; i++) {

			if (i == 0 || cpus->map[i].cpu != cpus->map[i - 1].cpu)

				cpus->map[j++].cpu = cpus->map[i].cpu;

			if (i == 0 || RC_CHK_ACCESS(cpus)->map[i].cpu != RC_CHK_ACCESS(cpus)->map[i - 1].cpu)

				RC_CHK_ACCESS(cpus)->map[j++].cpu = RC_CHK_ACCESS(cpus)->map[i].cpu;

		}

		cpus->nr = j;

		perf_cpu_map__set_nr(cpus, j);

		assert(j <= nr_cpus);

	}

	return cpus;
@@ -268,20 +275,20 @@ struct perf_cpu perf_cpu_map__cpu(const struct perf_cpu_map *cpus, int idx) 
		.cpu = -1

	};



	if (cpus && idx < cpus->nr)

		return cpus->map[idx];

	if (cpus && idx < RC_CHK_ACCESS(cpus)->nr)

		return RC_CHK_ACCESS(cpus)->map[idx];



	return result;

}



int perf_cpu_map__nr(const struct perf_cpu_map *cpus)

{

	return cpus ? cpus->nr : 1;

	return cpus ? RC_CHK_ACCESS(cpus)->nr : 1;

}



bool perf_cpu_map__empty(const struct perf_cpu_map *map)

{

	return map ? map->map[0].cpu == -1 : true;

	return map ? RC_CHK_ACCESS(map)->map[0].cpu == -1 : true;

}



int perf_cpu_map__idx(const struct perf_cpu_map *cpus, struct perf_cpu cpu)
@@ -292,10 +299,10 @@ int perf_cpu_map__idx(const struct perf_cpu_map *cpus, struct perf_cpu cpu) 
		return -1;



	low = 0;

	high = cpus->nr;

	high = RC_CHK_ACCESS(cpus)->nr;

	while (low < high) {

		int idx = (low + high) / 2;

		struct perf_cpu cpu_at_idx = cpus->map[idx];

		struct perf_cpu cpu_at_idx = RC_CHK_ACCESS(cpus)->map[idx];



		if (cpu_at_idx.cpu == cpu.cpu)

			return idx;
@@ -321,7 +328,7 @@ struct perf_cpu perf_cpu_map__max(const struct perf_cpu_map *map) 
	};



	// cpu_map__trim_new() qsort()s it, cpu_map__default_new() sorts it as well.

	return map->nr > 0 ? map->map[map->nr - 1] : result;

	return RC_CHK_ACCESS(map)->nr > 0 ? RC_CHK_ACCESS(map)->map[RC_CHK_ACCESS(map)->nr - 1] : result;

}



/** Is 'b' a subset of 'a'. */
@@ -329,15 +336,15 @@ bool perf_cpu_map__is_subset(const struct perf_cpu_map *a, const struct perf_cpu 
{

	if (a == b || !b)

		return true;

	if (!a || b->nr > a->nr)

	if (!a || RC_CHK_ACCESS(b)->nr > RC_CHK_ACCESS(a)->nr)

		return false;



	for (int i = 0, j = 0; i < a->nr; i++) {

		if (a->map[i].cpu > b->map[j].cpu)

	for (int i = 0, j = 0; i < RC_CHK_ACCESS(a)->nr; i++) {

		if (RC_CHK_ACCESS(a)->map[i].cpu > RC_CHK_ACCESS(b)->map[j].cpu)

			return false;

		if (a->map[i].cpu == b->map[j].cpu) {

		if (RC_CHK_ACCESS(a)->map[i].cpu == RC_CHK_ACCESS(b)->map[j].cpu) {

			j++;

			if (j == b->nr)

			if (j == RC_CHK_ACCESS(b)->nr)

				return true;

		}

	}
@@ -367,27 +374,27 @@ struct perf_cpu_map *perf_cpu_map__merge(struct perf_cpu_map *orig, 
		return perf_cpu_map__get(other);

	}



	tmp_len = orig->nr + other->nr;

	tmp_len = RC_CHK_ACCESS(orig)->nr + RC_CHK_ACCESS(other)->nr;

	tmp_cpus = malloc(tmp_len * sizeof(struct perf_cpu));

	if (!tmp_cpus)

		return NULL;



	/* Standard merge algorithm from wikipedia */

	i = j = k = 0;

	while (i < orig->nr && j < other->nr) {

		if (orig->map[i].cpu <= other->map[j].cpu) {

			if (orig->map[i].cpu == other->map[j].cpu)

	while (i < RC_CHK_ACCESS(orig)->nr && j < RC_CHK_ACCESS(other)->nr) {

		if (RC_CHK_ACCESS(orig)->map[i].cpu <= RC_CHK_ACCESS(other)->map[j].cpu) {

			if (RC_CHK_ACCESS(orig)->map[i].cpu == RC_CHK_ACCESS(other)->map[j].cpu)

				j++;

			tmp_cpus[k++] = orig->map[i++];

			tmp_cpus[k++] = RC_CHK_ACCESS(orig)->map[i++];

		} else

			tmp_cpus[k++] = other->map[j++];

			tmp_cpus[k++] = RC_CHK_ACCESS(other)->map[j++];

	}



	while (i < orig->nr)

		tmp_cpus[k++] = orig->map[i++];

	while (i < RC_CHK_ACCESS(orig)->nr)

		tmp_cpus[k++] = RC_CHK_ACCESS(orig)->map[i++];



	while (j < other->nr)

		tmp_cpus[k++] = other->map[j++];

	while (j < RC_CHK_ACCESS(other)->nr)

		tmp_cpus[k++] = RC_CHK_ACCESS(other)->map[j++];

	assert(k <= tmp_len);



	merged = cpu_map__trim_new(k, tmp_cpus);

tools/lib/perf/include/internal/cpumap.h

+3 −2
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 


#include <linux/refcount.h>

#include <perf/cpumap.h>

#include <internal/rc_check.h>



/**

 * A sized, reference counted, sorted array of integers representing CPU
@@ -12,7 +13,7 @@ 
 * gaps if CPU numbers were used. For events associated with a pid, rather than

 * a CPU, a single dummy map with an entry of -1 is used.

 */

struct perf_cpu_map {

DECLARE_RC_STRUCT(perf_cpu_map) {

	refcount_t	refcnt;

	/** Length of the map array. */

	int		nr;
@@ -32,6 +33,6 @@ void perf_cpu_map__set_nr(struct perf_cpu_map *map, int nr_cpus); 


static inline refcount_t *perf_cpu_map__refcnt(struct perf_cpu_map *map)

{

	return &map->refcnt;

	return &RC_CHK_ACCESS(map)->refcnt;

}

#endif /* __LIBPERF_INTERNAL_CPUMAP_H */

tools/perf/util/cpumap.c

+6 −6
Original line number Diff line number Diff line
@@ -77,9 +77,9 @@ static struct perf_cpu_map *cpu_map__from_entries(const struct perf_record_cpu_m 
			 * otherwise it would become 65535.

			 */

			if (data->cpus_data.cpu[i] == (u16) -1)

				map->map[i].cpu = -1;

				RC_CHK_ACCESS(map)->map[i].cpu = -1;

			else

				map->map[i].cpu = (int) data->cpus_data.cpu[i];

				RC_CHK_ACCESS(map)->map[i].cpu = (int) data->cpus_data.cpu[i];

		}

	}
@@ -107,7 +107,7 @@ static struct perf_cpu_map *cpu_map__from_mask(const struct perf_record_cpu_map_ 


		perf_record_cpu_map_data__read_one_mask(data, i, local_copy);

		for_each_set_bit(cpu, local_copy, 64)

			map->map[j++].cpu = cpu + cpus_per_i;

			RC_CHK_ACCESS(map)->map[j++].cpu = cpu + cpus_per_i;

	}

	return map;
@@ -124,11 +124,11 @@ static struct perf_cpu_map *cpu_map__from_range(const struct perf_record_cpu_map 
		return NULL;



	if (data->range_cpu_data.any_cpu)

		map->map[i++].cpu = -1;

		RC_CHK_ACCESS(map)->map[i++].cpu = -1;



	for (int cpu = data->range_cpu_data.start_cpu; cpu <= data->range_cpu_data.end_cpu;

	     i++, cpu++)

		map->map[i].cpu = cpu;

		RC_CHK_ACCESS(map)->map[i].cpu = cpu;



	return map;

}
@@ -164,7 +164,7 @@ struct perf_cpu_map *perf_cpu_map__empty_new(int nr) 


	if (cpus != NULL) {

		for (int i = 0; i < nr; i++)

			cpus->map[i].cpu = -1;

			RC_CHK_ACCESS(cpus)->map[i].cpu = -1;

	}



	return cpus;

tools/perf/util/pmu.c

+2 −2
Original line number Diff line number Diff line
@@ -2015,9 +2015,9 @@ int perf_pmu__cpus_match(struct perf_pmu *pmu, struct perf_cpu_map *cpus, 


	perf_cpu_map__for_each_cpu(cpu, i, cpus) {

		if (!perf_cpu_map__has(pmu_cpus, cpu))

			unmatched_cpus->map[unmatched_nr++] = cpu;

			RC_CHK_ACCESS(unmatched_cpus)->map[unmatched_nr++] = cpu;

		else

			matched_cpus->map[matched_nr++] = cpu;

			RC_CHK_ACCESS(matched_cpus)->map[matched_nr++] = cpu;

	}



	perf_cpu_map__set_nr(unmatched_cpus, unmatched_nr);