[PATCH v5 12/17] perf map: Changes to reference counting

Ian Rogers
2023-03-20T21:25:45Z

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>
---
tools/perf/tests/code-reading.c | 1 +
tools/perf/tests/hists_cumulate.c | 10 ++++
tools/perf/tests/hists_filter.c | 10 ++++
tools/perf/tests/hists_link.c | 18 +++++-
tools/perf/tests/hists_output.c | 10 ++++
tools/perf/tests/mmap-thread-lookup.c | 1 +
tools/perf/util/callchain.c | 9 +--
tools/perf/util/event.c | 6 +-
tools/perf/util/hist.c | 10 ++--
tools/perf/util/machine.c | 79 ++++++++++++++++-----------
tools/perf/util/map.c | 2 +-
11 files changed, 112 insertions(+), 44 deletions(-)

diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
index 1545fcaa95c6..efe026a35010 100644
--- a/tools/perf/tests/code-reading.c
+++ b/tools/perf/tests/code-reading.c
@@ -366,6 +366,7 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode,
}
pr_debug("Bytes read match those read by objdump\n");
out:
+ map__put(al.map);
return err;
}

diff --git a/tools/perf/tests/hists_cumulate.c b/tools/perf/tests/hists_cumulate.c
index f00ec9abdbcd..8c0e3f334747 100644
--- a/tools/perf/tests/hists_cumulate.c
+++ b/tools/perf/tests/hists_cumulate.c
@@ -112,6 +112,7 @@ static int add_hist_entries(struct hists *hists, struct machine *machine)
}

fake_samples[i].thread = al.thread;
+ map__put(fake_samples[i].map);
fake_samples[i].map = al.map;
fake_samples[i].sym = al.sym;
}
@@ -147,6 +148,14 @@ static void del_hist_entries(struct hists *hists)
}
}

+static void put_fake_samples(void)
+{
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(fake_samples); i++)
+ map__put(fake_samples[i].map);
+}
+
typedef int (*test_fn_t)(struct evsel *, struct machine *);

#define COMM(he) (thread__comm_str(he->thread))
@@ -733,6 +742,7 @@ static int test__hists_cumulate(struct test_suite *test __maybe_unused, int subt
/* tear down everything */
evlist__delete(evlist);
machines__exit(&machines);
+ put_fake_samples();

return err;
}
diff --git a/tools/perf/tests/hists_filter.c b/tools/perf/tests/hists_filter.c
index 7c552549f4a4..98eff5935a1c 100644
--- a/tools/perf/tests/hists_filter.c
+++ b/tools/perf/tests/hists_filter.c
@@ -89,6 +89,7 @@ static int add_hist_entries(struct evlist *evlist,
}

fake_samples[i].thread = al.thread;
+ map__put(fake_samples[i].map);
fake_samples[i].map = al.map;
fake_samples[i].sym = al.sym;
}
@@ -101,6 +102,14 @@ static int add_hist_entries(struct evlist *evlist,
return TEST_FAIL;
}

+static void put_fake_samples(void)
+{
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(fake_samples); i++)
+ map__put(fake_samples[i].map);
+}
+
static int test__hists_filter(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
{
int err = TEST_FAIL;
@@ -322,6 +331,7 @@ static int test__hists_filter(struct test_suite *test __maybe_unused, int subtes
evlist__delete(evlist);
reset_output_field();
machines__exit(&machines);
+ put_fake_samples();

return err;
}
diff --git a/tools/perf/tests/hists_link.c b/tools/perf/tests/hists_link.c
index e7e4ee57ce04..64ce8097889c 100644
--- a/tools/perf/tests/hists_link.c
+++ b/tools/perf/tests/hists_link.c
@@ -6,6 +6,7 @@
#include "evsel.h"
#include "evlist.h"
#include "machine.h"
+#include "map.h"
#include "parse-events.h"
#include "hists_common.h"
#include "util/mmap.h"
@@ -94,6 +95,7 @@ static int add_hist_entries(struct evlist *evlist, struct machine *machine)
}

fake_common_samples[k].thread = al.thread;
+ map__put(fake_common_samples[k].map);
fake_common_samples[k].map = al.map;
fake_common_samples[k].sym = al.sym;
}
@@ -126,11 +128,24 @@ static int add_hist_entries(struct evlist *evlist, struct machine *machine)
return -1;
}

+static void put_fake_samples(void)
+{
+ size_t i, j;
+
+ for (i = 0; i < ARRAY_SIZE(fake_common_samples); i++)
+ map__put(fake_common_samples[i].map);
+ for (i = 0; i < ARRAY_SIZE(fake_samples); i++) {
+ for (j = 0; j < ARRAY_SIZE(fake_samples[0]); j++)
+ map__put(fake_samples[i][j].map);
+ }
+}
+
static int find_sample(struct sample *samples, size_t nr_samples,
struct thread *t, struct map *m, struct symbol *s)
{
while (nr_samples--) {
- if (samples->thread == t && samples->map == m &&
+ if (samples->thread == t &&
+ samples->map == m &&
samples->sym == s)
return 1;
samples++;
@@ -336,6 +351,7 @@ static int test__hists_link(struct test_suite *test __maybe_unused, int subtest
evlist__delete(evlist);
reset_output_field();
machines__exit(&machines);
+ put_fake_samples();

return err;
}
diff --git a/tools/perf/tests/hists_output.c b/tools/perf/tests/hists_output.c
index 428d11a938f2..cebd5226bb12 100644
--- a/tools/perf/tests/hists_output.c
+++ b/tools/perf/tests/hists_output.c
@@ -78,6 +78,7 @@ static int add_hist_entries(struct hists *hists, struct machine *machine)
}

fake_samples[i].thread = al.thread;
+ map__put(fake_samples[i].map);
fake_samples[i].map = al.map;
fake_samples[i].sym = al.sym;
}
@@ -113,6 +114,14 @@ static void del_hist_entries(struct hists *hists)
}
}

+static void put_fake_samples(void)
+{
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(fake_samples); i++)
+ map__put(fake_samples[i].map);
+}
+
typedef int (*test_fn_t)(struct evsel *, struct machine *);

#define COMM(he) (thread__comm_str(he->thread))
@@ -620,6 +629,7 @@ static int test__hists_output(struct test_suite *test __maybe_unused, int subtes
/* tear down everything */
evlist__delete(evlist);
machines__exit(&machines);
+ put_fake_samples();

return err;
}
diff --git a/tools/perf/tests/mmap-thread-lookup.c b/tools/perf/tests/mmap-thread-lookup.c
index 5cc4644e353d..898eda55b7a8 100644
--- a/tools/perf/tests/mmap-thread-lookup.c
+++ b/tools/perf/tests/mmap-thread-lookup.c
@@ -203,6 +203,7 @@ static int mmap_events(synth_cb synth)
}

pr_debug("map %p, addr %" PRIx64 "\n", al.map, map__start(al.map));
+ map__put(al.map);
}

machine__delete_threads(machine);
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 9e9c39dd9d2b..78dc7b6f7ff7 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -589,7 +589,7 @@ fill_node(struct callchain_node *node, struct callchain_cursor *cursor)
}
call->ip = cursor_node->ip;
call->ms = cursor_node->ms;
- map__get(call->ms.map);
+ call->ms.map = map__get(call->ms.map);
call->srcline = cursor_node->srcline;

if (cursor_node->branch) {
@@ -1067,7 +1067,7 @@ int callchain_cursor_append(struct callchain_cursor *cursor,
node->ip = ip;
map__zput(node->ms.map);
node->ms = *ms;
- map__get(node->ms.map);
+ node->ms.map = map__get(node->ms.map);
node->branch = branch;
node->nr_loop_iter = nr_loop_iter;
node->iter_cycles = iter_cycles;
@@ -1115,7 +1115,8 @@ int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *
struct machine *machine = maps__machine(node->ms.maps);

al->maps = node->ms.maps;
- al->map = node->ms.map;
+ map__put(al->map);
+ al->map = map__get(node->ms.map);
al->sym = node->ms.sym;
al->srcline = node->srcline;
al->addr = node->ip;
@@ -1528,7 +1529,7 @@ int callchain_node__make_parent_list(struct callchain_node *node)
goto out;
*new = *chain;
new->has_children = false;
- map__get(new->ms.map);
+ new->ms.map = map__get(new->ms.map);
list_add_tail(&new->list, &head);
}
parent = parent->parent;
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);
}

diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index fdf0562d2fd3..02b4bf31b1a7 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -450,7 +450,7 @@ static int hist_entry__init(struct hist_entry *he,
memset(&he->stat, 0, sizeof(he->stat));
}

- map__get(he->ms.map);
+ he->ms.map = map__get(he->ms.map);

if (he->branch_info) {
/*
@@ -465,13 +465,13 @@ static int hist_entry__init(struct hist_entry *he,
memcpy(he->branch_info, template->branch_info,
sizeof(*he->branch_info));

- map__get(he->branch_info->from.ms.map);
- map__get(he->branch_info->to.ms.map);
+ he->branch_info->from.ms.map = map__get(he->branch_info->from.ms.map);
+ he->branch_info->to.ms.map = map__get(he->branch_info->to.ms.map);
}

if (he->mem_info) {
- map__get(he->mem_info->iaddr.ms.map);
- map__get(he->mem_info->daddr.ms.map);
+ he->mem_info->iaddr.ms.map = map__get(he->mem_info->iaddr.ms.map);
+ he->mem_info->daddr.ms.map = map__get(he->mem_info->daddr.ms.map);
}

if (hist_entry__has_callchains(he) && symbol_conf.use_callchain)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 916d98885128..502e97010a3c 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -880,21 +880,29 @@ static int machine__process_ksymbol_register(struct machine *machine,
struct symbol *sym;
struct dso *dso;
struct map *map = maps__find(machine__kernel_maps(machine), event->ksymbol.addr);
+ bool put_map = false;
+ int err = 0;

if (!map) {
- int err;
-
dso = dso__new(event->ksymbol.name);
- if (dso) {
- dso->kernel = DSO_SPACE__KERNEL;
- map = map__new2(0, dso);
- dso__put(dso);
- }

- if (!dso || !map) {
- return -ENOMEM;
+ if (!dso) {
+ err = -ENOMEM;
+ goto out;
}
-
+ dso->kernel = DSO_SPACE__KERNEL;
+ map = map__new2(0, dso);
+ dso__put(dso);
+ if (!map) {
+ err = -ENOMEM;
+ goto out;
+ }
+ /*
+ * The inserted map has a get on it, we need to put to release
+ * the reference count here, but do it after all accesses are
+ * done.
+ */
+ put_map = true;
if (event->ksymbol.ksym_type == PERF_RECORD_KSYMBOL_TYPE_OOL) {
dso->binary_type = DSO_BINARY_TYPE__OOL;
dso->data.file_size = event->ksymbol.len;
@@ -904,9 +912,10 @@ static int machine__process_ksymbol_register(struct machine *machine,
map->start = event->ksymbol.addr;
map->end = map__start(map) + event->ksymbol.len;
err = maps__insert(machine__kernel_maps(machine), map);
- map__put(map);
- if (err)
- return err;
+ if (err) {
+ err = -ENOMEM;
+ goto out;
+ }

dso__set_loaded(dso);

@@ -921,10 +930,15 @@ static int machine__process_ksymbol_register(struct machine *machine,
sym = symbol__new(map__map_ip(map, map__start(map)),
event->ksymbol.len,
0, 0, event->ksymbol.name);
- if (!sym)
- return -ENOMEM;
+ if (!sym) {
+ err = -ENOMEM;
+ goto out;
+ }
dso__insert_symbol(dso, sym);
- return 0;
+out:
+ if (put_map)
+ map__put(map);
+ return err;
}

static int machine__process_ksymbol_unregister(struct machine *machine,
@@ -1026,13 +1040,11 @@ static struct map *machine__addnew_module_map(struct machine *machine, u64 start
goto out;

err = maps__insert(machine__kernel_maps(machine), map);
-
- /* Put the map here because maps__insert already got it */
- map__put(map);
-
/* If maps__insert failed, return NULL. */
- if (err)
+ if (err) {
+ map__put(map);
map = NULL;
+ }
out:
/* put the dso here, corresponding to machine__findnew_module_dso */
dso__put(dso);
@@ -1324,6 +1336,7 @@ __machine__create_kernel_maps(struct machine *machine, struct dso *kernel)
/* In case of renewal the kernel map, destroy previous one */
machine__destroy_kernel_maps(machine);

+ map__put(machine->vmlinux_map);
machine->vmlinux_map = map__new2(0, kernel);
if (machine->vmlinux_map == NULL)
return -ENOMEM;
@@ -1612,7 +1625,7 @@ static int machine__create_module(void *arg, const char *name, u64 start,
map->end = start + size;

dso__kernel_module_get_build_id(map__dso(map), machine->root_dir);
-
+ map__put(map);
return 0;
}

@@ -1658,16 +1671,18 @@ static void machine__set_kernel_mmap(struct machine *machine,
static int machine__update_kernel_mmap(struct machine *machine,
u64 start, u64 end)
{
- struct map *map = machine__kernel_map(machine);
+ struct map *orig, *updated;
int err;

- map__get(map);
- maps__remove(machine__kernel_maps(machine), map);
+ orig = machine->vmlinux_map;
+ updated = map__get(orig);

+ machine->vmlinux_map = updated;
machine__set_kernel_mmap(machine, start, end);
+ maps__remove(machine__kernel_maps(machine), orig);
+ err = maps__insert(machine__kernel_maps(machine), updated);
+ map__put(orig);

- err = maps__insert(machine__kernel_maps(machine), map);
- map__put(map);
return err;
}

@@ -2294,7 +2309,7 @@ static int add_callchain_ip(struct thread *thread,
{
struct map_symbol ms;
struct addr_location al;
- int nr_loop_iter = 0;
+ int nr_loop_iter = 0, err;
u64 iter_cycles = 0;
const char *srcline = NULL;

@@ -2355,9 +2370,11 @@ static int add_callchain_ip(struct thread *thread,
ms.map = al.map;
ms.sym = al.sym;
srcline = callchain_srcline(&ms, al.addr);
- return callchain_cursor_append(cursor, ip, &ms,
- branch, flags, nr_loop_iter,
- iter_cycles, branch_from, srcline);
+ err = callchain_cursor_append(cursor, ip, &ms,
+ branch, flags, nr_loop_iter,
+ iter_cycles, branch_from, srcline);
+ map__put(al.map);
+ return err;
}

struct branch_info *sample__resolve_bstack(struct perf_sample *sample,
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 1fe367e2cf19..acbc37359e06 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -410,7 +410,7 @@ struct map *map__clone(struct map *from)
map = memdup(from, size);
if (map != NULL) {
refcount_set(&map->refcnt, 1);
- dso__get(dso);
+ map->dso = dso__get(dso);
}

return map;
--
2.40.0.rc1.284.g88254d51c5-goog