From 8f12692b7e61e5fb5d3e4f6692d6675f62eeebdc Mon Sep 17 00:00:00 2001
From: Ian Rogers <irogers@google.com>
Date: Wed, 19 Apr 2023 10:48:37 -0300
Subject: [PATCH] perf maps: Add reference count checking
Add reference count checking to make sure of good use of get and put.
Add and use accessors to reduce RC_CHK clutter.
The only significant issue was in tests/thread-maps-share.c where
reference counts were released in the reverse order to acquisition,
leading to a use after put. This was fixed by reversing the put order.
Committer notes:
Extracted from a larger patch removing bits that were covered by the use
of pre-existing maps__ accessors (e.g. maps__nr_maps()) and new ones
added (maps__refcnt()) to reduce RC_CHK_ACCESS(maps)-> source code
pollution.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Link: https://lore.kernel.org/lkml/20230407230405.2931830-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/tests/thread-maps-share.c | 8 ++--
tools/perf/util/maps.c | 47 +++++++++++++-----------
tools/perf/util/maps.h | 19 +++++-----
tools/perf/util/symbol.c | 13 ++++---
tools/perf/util/unwind-libdw.c | 2 +-
tools/perf/util/unwind-libunwind-local.c | 2 +-
tools/perf/util/unwind-libunwind.c | 2 +-
7 files changed, 50 insertions(+), 43 deletions(-)
diff --git a/tools/perf/tests/thread-maps-share.c b/tools/perf/tests/thread-maps-share.c
index caf8fbe7c4409..75ce8aedfc789 100644
--- a/tools/perf/tests/thread-maps-share.c
+++ b/tools/perf/tests/thread-maps-share.c
@@ -46,9 +46,9 @@ static int test__thread_maps_share(struct test_suite *test __maybe_unused, int s
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(maps)), 4);
/* test the maps pointer is shared */
- TEST_ASSERT_VAL("maps don't match", maps == t1->maps);
- TEST_ASSERT_VAL("maps don't match", maps == t2->maps);
- TEST_ASSERT_VAL("maps don't match", maps == t3->maps);
+ TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(maps) == RC_CHK_ACCESS(t1->maps));
+ TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(maps) == RC_CHK_ACCESS(t2->maps));
+ TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(maps) == RC_CHK_ACCESS(t3->maps));
/*
* Verify the other leader was created by previous call.
@@ -73,7 +73,7 @@ static int test__thread_maps_share(struct test_suite *test __maybe_unused, int s
other_maps = other->maps;
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(other_maps)), 2);
- TEST_ASSERT_VAL("maps don't match", other_maps == other_leader->maps);
+ TEST_ASSERT_VAL("maps don't match", RC_CHK_ACCESS(other_maps) == RC_CHK_ACCESS(other_leader->maps));
/* release thread group */
thread__put(leader);
diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c
index 953dc20d55d7d..8a13396acd1a0 100644
--- a/tools/perf/util/maps.c
+++ b/tools/perf/util/maps.c
@@ -13,12 +13,12 @@
static void maps__init(struct maps *maps, struct machine *machine)
{
refcount_set(maps__refcnt(maps), 1);
- maps->entries = RB_ROOT;
init_rwsem(maps__lock(maps));
- maps->machine = machine;
- maps->last_search_by_name = NULL;
- maps->nr_maps = 0;
- maps->maps_by_name = NULL;
+ RC_CHK_ACCESS(maps)->entries = RB_ROOT;
+ RC_CHK_ACCESS(maps)->machine = machine;
+ RC_CHK_ACCESS(maps)->last_search_by_name = NULL;
+ RC_CHK_ACCESS(maps)->nr_maps = 0;
+ RC_CHK_ACCESS(maps)->maps_by_name = NULL;
}
static void __maps__free_maps_by_name(struct maps *maps)
@@ -29,8 +29,8 @@ static void __maps__free_maps_by_name(struct maps *maps)
for (unsigned int i = 0; i < maps__nr_maps(maps); i++)
map__put(maps__maps_by_name(maps)[i]);
- zfree(&maps->maps_by_name);
- maps->nr_maps_allocated = 0;
+ zfree(&RC_CHK_ACCESS(maps)->maps_by_name);
+ RC_CHK_ACCESS(maps)->nr_maps_allocated = 0;
}
static int __maps__insert(struct maps *maps, struct map *map)
@@ -71,7 +71,7 @@ int maps__insert(struct maps *maps, struct map *map)
if (err)
goto out;
- ++maps->nr_maps;
+ ++RC_CHK_ACCESS(maps)->nr_maps;
if (dso && dso->kernel) {
struct kmap *kmap = map__kmap(map);
@@ -88,7 +88,7 @@ int maps__insert(struct maps *maps, struct map *map)
* inserted map and resort.
*/
if (maps__maps_by_name(maps)) {
- if (maps__nr_maps(maps) > maps->nr_maps_allocated) {
+ if (maps__nr_maps(maps) > RC_CHK_ACCESS(maps)->nr_maps_allocated) {
int nr_allocate = maps__nr_maps(maps) * 2;
struct map **maps_by_name = realloc(maps__maps_by_name(maps),
nr_allocate * sizeof(map));
@@ -99,8 +99,8 @@ int maps__insert(struct maps *maps, struct map *map)
goto out;
}
- maps->maps_by_name = maps_by_name;
- maps->nr_maps_allocated = nr_allocate;
+ RC_CHK_ACCESS(maps)->maps_by_name = maps_by_name;
+ RC_CHK_ACCESS(maps)->nr_maps_allocated = nr_allocate;
}
maps__maps_by_name(maps)[maps__nr_maps(maps) - 1] = map__get(map);
__maps__sort_by_name(maps);
@@ -122,15 +122,15 @@ void maps__remove(struct maps *maps, struct map *map)
struct map_rb_node *rb_node;
down_write(maps__lock(maps));
- if (maps->last_search_by_name == map)
- maps->last_search_by_name = NULL;
+ if (RC_CHK_ACCESS(maps)->last_search_by_name == map)
+ RC_CHK_ACCESS(maps)->last_search_by_name = NULL;
rb_node = maps__find_node(maps, map);
assert(rb_node->map == map);
__maps__remove(maps, rb_node);
if (maps__maps_by_name(maps))
__maps__free_maps_by_name(maps);
- --maps->nr_maps;
+ --RC_CHK_ACCESS(maps)->nr_maps;
up_write(maps__lock(maps));
}
@@ -162,33 +162,38 @@ bool maps__empty(struct maps *maps)
struct maps *maps__new(struct machine *machine)
{
- struct maps *maps = zalloc(sizeof(*maps));
+ struct maps *result;
+ RC_STRUCT(maps) *maps = zalloc(sizeof(*maps));
- if (maps != NULL)
- maps__init(maps, machine);
+ if (ADD_RC_CHK(result, maps))
+ maps__init(result, machine);
- return maps;
+ return result;
}
void maps__delete(struct maps *maps)
{
maps__exit(maps);
unwind__finish_access(maps);
- free(maps);
+ RC_CHK_FREE(maps);
}
struct maps *maps__get(struct maps *maps)
{
- if (maps)
+ struct maps *result;
+
+ if (RC_CHK_GET(result, maps))
refcount_inc(maps__refcnt(maps));
- return maps;
+ return result;
}
void maps__put(struct maps *maps)
{
if (maps && refcount_dec_and_test(maps__refcnt(maps)))
maps__delete(maps);
+ else
+ RC_CHK_PUT(maps);
}
struct symbol *maps__find_symbol(struct maps *maps, u64 addr, struct map **mapp)
diff --git a/tools/perf/util/maps.h b/tools/perf/util/maps.h
index cfb1b79d16713..d2963456cfbe7 100644
--- a/tools/perf/util/maps.h
+++ b/tools/perf/util/maps.h
@@ -8,6 +8,7 @@
#include <stdbool.h>
#include <linux/types.h>
#include "rwsem.h"
+#include <internal/rc_check.h>
struct ref_reloc_sym;
struct machine;
@@ -32,7 +33,7 @@ struct map *maps__find(struct maps *maps, u64 addr);
for (map = maps__first(maps), next = map_rb_node__next(map); map; \
map = next, next = map_rb_node__next(map))
-struct maps {
+DECLARE_RC_STRUCT(maps) {
struct rb_root entries;
struct rw_semaphore lock;
struct machine *machine;
@@ -65,43 +66,43 @@ void maps__put(struct maps *maps);
static inline struct rb_root *maps__entries(struct maps *maps)
{
- return &maps->entries;
+ return &RC_CHK_ACCESS(maps)->entries;
}
static inline struct machine *maps__machine(struct maps *maps)
{
- return maps->machine;
+ return RC_CHK_ACCESS(maps)->machine;
}
static inline struct rw_semaphore *maps__lock(struct maps *maps)
{
- return &maps->lock;
+ return &RC_CHK_ACCESS(maps)->lock;
}
static inline struct map **maps__maps_by_name(struct maps *maps)
{
- return maps->maps_by_name;
+ return RC_CHK_ACCESS(maps)->maps_by_name;
}
static inline unsigned int maps__nr_maps(const struct maps *maps)
{
- return maps->nr_maps;
+ return RC_CHK_ACCESS(maps)->nr_maps;
}
static inline refcount_t *maps__refcnt(struct maps *maps)
{
- return &maps->refcnt;
+ return &RC_CHK_ACCESS(maps)->refcnt;
}
#ifdef HAVE_LIBUNWIND_SUPPORT
static inline void *maps__addr_space(struct maps *maps)
{
- return maps->addr_space;
+ return RC_CHK_ACCESS(maps)->addr_space;
}
static inline const struct unwind_libunwind_ops *maps__unwind_libunwind_ops(const struct maps *maps)
{
- return maps->unwind_libunwind_ops;
+ return RC_CHK_ACCESS(maps)->unwind_libunwind_ops;
}
#endif
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index e7f63670688e8..01fa5560a0bbe 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -2096,8 +2096,8 @@ static int map__groups__sort_by_name_from_rbtree(struct maps *maps)
up_read(maps__lock(maps));
down_write(maps__lock(maps));
- maps->maps_by_name = maps_by_name;
- maps->nr_maps_allocated = maps__nr_maps(maps);
+ RC_CHK_ACCESS(maps)->maps_by_name = maps_by_name;
+ RC_CHK_ACCESS(maps)->nr_maps_allocated = maps__nr_maps(maps);
maps__for_each_entry(maps, rb_node)
maps_by_name[i++] = map__get(rb_node->map);
@@ -2132,11 +2132,12 @@ struct map *maps__find_by_name(struct maps *maps, const char *name)
down_read(maps__lock(maps));
- if (maps->last_search_by_name) {
- const struct dso *dso = map__dso(maps->last_search_by_name);
+
+ if (RC_CHK_ACCESS(maps)->last_search_by_name) {
+ const struct dso *dso = map__dso(RC_CHK_ACCESS(maps)->last_search_by_name);
if (strcmp(dso->short_name, name) == 0) {
- map = maps->last_search_by_name;
+ map = RC_CHK_ACCESS(maps)->last_search_by_name;
goto out_unlock;
}
}
@@ -2156,7 +2157,7 @@ struct map *maps__find_by_name(struct maps *maps, const char *name)
map = rb_node->map;
dso = map__dso(map);
if (strcmp(dso->short_name, name) == 0) {
- maps->last_search_by_name = map;
+ RC_CHK_ACCESS(maps)->last_search_by_name = map;
goto out_unlock;
}
}
diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c
index 9565f9906e5da..bdccfc511b7e2 100644
--- a/tools/perf/util/unwind-libdw.c
+++ b/tools/perf/util/unwind-libdw.c
@@ -230,7 +230,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
struct unwind_info *ui, ui_buf = {
.sample = data,
.thread = thread,
- .machine = thread->maps->machine,
+ .machine = RC_CHK_ACCESS(thread->maps)->machine,
.cb = cb,
.arg = arg,
.max_stack = max_stack,
diff --git a/tools/perf/util/unwind-libunwind-local.c b/tools/perf/util/unwind-libunwind-local.c
index f9a52af48de45..83dd79dcd597e 100644
--- a/tools/perf/util/unwind-libunwind-local.c
+++ b/tools/perf/util/unwind-libunwind-local.c
@@ -677,7 +677,7 @@ static int _unwind__prepare_access(struct maps *maps)
{
void *addr_space = unw_create_addr_space(&accessors, 0);
- maps->addr_space = addr_space;
+ RC_CHK_ACCESS(maps)->addr_space = addr_space;
if (!addr_space) {
pr_err("unwind: Can't create unwind address space.\n");
return -ENOMEM;
diff --git a/tools/perf/util/unwind-libunwind.c b/tools/perf/util/unwind-libunwind.c
index 4378daaafcd3b..b54968e6a4e4c 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/tools/perf/util/unwind-libunwind.c
@@ -14,7 +14,7 @@ struct unwind_libunwind_ops __weak *arm64_unwind_libunwind_ops;
static void unwind__register_ops(struct maps *maps, struct unwind_libunwind_ops *ops)
{
- maps->unwind_libunwind_ops = ops;
+ RC_CHK_ACCESS(maps)->unwind_libunwind_ops = ops;
}
int unwind__prepare_access(struct maps *maps, struct map *map, bool *initialized)
--
2.30.2