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: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 8 insertions, 8 deletions

diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index 240557de129e..75d9c73e0184 100644
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -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;
diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 760c848c9fa2..65d0eb9a740a 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -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);