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perf maps: Add maps__refcnt() accessor to allow checking maps pointer

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To remove one more direct access to 'struct maps' so that we can
intercept accesses to its instantiations and refcount check it to catch
use after free, etc.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2023-04-18 17:33:48 -03:00
parent 3ad1be6fae
commit fe693d951e
3 changed files with 14 additions and 9 deletions
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12
tools/perf/tests/thread-maps-share.c
View File

@ -43,7 +43,7 @@ static int test__thread_maps_share(struct test_suite *test __maybe_unused, int s
leader && t1 && t2 && t3 && other);
maps = leader->maps;
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&maps->refcnt), 4);
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);
@ -71,25 +71,25 @@ static int test__thread_maps_share(struct test_suite *test __maybe_unused, int s
machine__remove_thread(machine, other_leader);
other_maps = other->maps;
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&other_maps->refcnt), 2);
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(other_maps)), 2);
TEST_ASSERT_VAL("maps don't match", other_maps == other_leader->maps);
/* release thread group */
thread__put(leader);
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&maps->refcnt), 3);
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(maps)), 3);
thread__put(t1);
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&maps->refcnt), 2);
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(maps)), 2);
thread__put(t2);
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&maps->refcnt), 1);
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(maps)), 1);
thread__put(t3);
/* release other group */
thread__put(other_leader);
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&other_maps->refcnt), 1);
TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(maps__refcnt(other_maps)), 1);
thread__put(other);

6
tools/perf/util/maps.c
View File

@ -12,13 +12,13 @@
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;
refcount_set(&maps->refcnt, 1);
}
static void __maps__free_maps_by_name(struct maps *maps)
@ -180,14 +180,14 @@ void maps__delete(struct maps *maps)
struct maps *maps__get(struct maps *maps)
{
if (maps)
refcount_inc(&maps->refcnt);
refcount_inc(maps__refcnt(maps));
return maps;
}
void maps__put(struct maps *maps)
{
if (maps && refcount_dec_and_test(&maps->refcnt))
if (maps && refcount_dec_and_test(maps__refcnt(maps)))
maps__delete(maps);
}

5
tools/perf/util/maps.h
View File

@ -88,6 +88,11 @@ static inline unsigned int maps__nr_maps(const struct maps *maps)
return maps->nr_maps;
}
static inline refcount_t *maps__refcnt(struct maps *maps)
{
return &maps->refcnt;
}
#ifdef HAVE_LIBUNWIND_SUPPORT
static inline void *maps__addr_space(struct maps *maps)
{