From ec417ad4c691b5d90ab13cf26789e8719468ae39 Mon Sep 17 00:00:00 2001
From: Ian Rogers <irogers@google.com>
Date: Tue, 4 Apr 2023 13:59:49 -0700
Subject: perf map: Changes to reference counting

When a pointer to a map exists do a get, when that pointer is
overwritten or freed, put the map. This avoids issues with gets and
puts being inconsistently used causing, use after puts, etc. For
example, the map in struct addr_location is changed to hold a
reference count. Reference count checking and address sanitizer were
used to identify issues.

Signed-off-by: Ian Rogers <irogers@google.com>
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: Stephane Eranian <eranian@google.com>
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/r/20230404205954.2245628-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/event.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

(limited to 'tools/perf/util/event.c')

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 2712d1a8264e..13f7f85e92e1 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -485,13 +485,14 @@ size_t perf_event__fprintf_text_poke(union perf_event *event, struct machine *ma
 	if (machine) {
 		struct addr_location al;
 
-		al.map = maps__find(machine__kernel_maps(machine), tp->addr);
+		al.map = map__get(maps__find(machine__kernel_maps(machine), tp->addr));
 		if (al.map && map__load(al.map) >= 0) {
 			al.addr = map__map_ip(al.map, tp->addr);
 			al.sym = map__find_symbol(al.map, al.addr);
 			if (al.sym)
 				ret += symbol__fprintf_symname_offs(al.sym, &al, fp);
 		}
+		map__put(al.map);
 	}
 	ret += fprintf(fp, " old len %u new len %u\n", tp->old_len, tp->new_len);
 	old = true;
@@ -614,7 +615,7 @@ struct map *thread__find_map(struct thread *thread, u8 cpumode, u64 addr,
 		return NULL;
 	}
 
-	al->map = maps__find(maps, al->addr);
+	al->map = map__get(maps__find(maps, al->addr));
 	if (al->map != NULL) {
 		/*
 		 * Kernel maps might be changed when loading symbols so loading
@@ -773,6 +774,7 @@ int machine__resolve(struct machine *machine, struct addr_location *al,
  */
 void addr_location__put(struct addr_location *al)
 {
+	map__zput(al->map);
 	thread__zput(al->thread);
 }
 
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