[PATCH v5 26/50] perf maps: Get map before returning in maps__find
From: Ian Rogers
Date: Mon Nov 27 2023 - 17:12:20 EST
Finding a map is done under a lock, returning the map without a
reference count means it can be removed without notice and causing
uses after free. Grab a reference count to the map within the lock
region and return this. Fix up locations that need a map__put
following this.
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
tools/perf/arch/x86/tests/dwarf-unwind.c | 1 +
tools/perf/tests/vmlinux-kallsyms.c | 5 ++---
tools/perf/util/bpf-event.c | 1 +
tools/perf/util/event.c | 4 ++--
tools/perf/util/machine.c | 22 ++++++++--------------
tools/perf/util/maps.c | 17 ++++++++++-------
tools/perf/util/symbol.c | 3 ++-
7 files changed, 26 insertions(+), 27 deletions(-)
diff --git a/tools/perf/arch/x86/tests/dwarf-unwind.c b/tools/perf/arch/x86/tests/dwarf-unwind.c
index 5bfec3345d59..c05c0a85dad4 100644
--- a/tools/perf/arch/x86/tests/dwarf-unwind.c
+++ b/tools/perf/arch/x86/tests/dwarf-unwind.c
@@ -34,6 +34,7 @@ static int sample_ustack(struct perf_sample *sample,
}
stack_size = map__end(map) - sp;
+ map__put(map);
stack_size = stack_size > STACK_SIZE ? STACK_SIZE : stack_size;
memcpy(buf, (void *) sp, stack_size);
diff --git a/tools/perf/tests/vmlinux-kallsyms.c b/tools/perf/tests/vmlinux-kallsyms.c
index 822f893e67d5..e808e6fc8f76 100644
--- a/tools/perf/tests/vmlinux-kallsyms.c
+++ b/tools/perf/tests/vmlinux-kallsyms.c
@@ -151,10 +151,8 @@ static int test__vmlinux_matches_kallsyms_cb2(struct map *map, void *data)
u64 mem_end = map__unmap_ip(args->vmlinux_map, map__end(map));
pair = maps__find(args->kallsyms.kmaps, mem_start);
- if (pair == NULL || map__priv(pair))
- return 0;
- if (map__start(pair) == mem_start) {
+ if (pair != NULL && !map__priv(pair) && map__start(pair) == mem_start) {
struct dso *dso = map__dso(map);
if (!args->header_printed) {
@@ -170,6 +168,7 @@ static int test__vmlinux_matches_kallsyms_cb2(struct map *map, void *data)
pr_info(" %s\n", dso->name);
map__set_priv(pair, 1);
}
+ map__put(pair);
return 0;
}
diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index 830711cae30d..d07fd5ffa823 100644
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -63,6 +63,7 @@ static int machine__process_bpf_event_load(struct machine *machine,
dso->bpf_prog.id = id;
dso->bpf_prog.sub_id = i;
dso->bpf_prog.env = env;
+ map__put(map);
}
}
return 0;
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 68f45e9e63b6..198903157f9e 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -511,7 +511,7 @@ size_t perf_event__fprintf_text_poke(union perf_event *event, struct machine *ma
struct addr_location al;
addr_location__init(&al);
- al.map = map__get(maps__find(machine__kernel_maps(machine), tp->addr));
+ al.map = 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);
@@ -641,7 +641,7 @@ struct map *thread__find_map(struct thread *thread, u8 cpumode, u64 addr,
return NULL;
}
al->maps = maps__get(maps);
- al->map = map__get(maps__find(maps, al->addr));
+ al->map = maps__find(maps, al->addr);
if (al->map != NULL) {
/*
* Kernel maps might be changed when loading symbols so loading
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index ab345604f274..1112a9dbb21a 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -897,7 +897,6 @@ 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) {
@@ -914,12 +913,6 @@ static int machine__process_ksymbol_register(struct machine *machine,
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;
@@ -953,8 +946,7 @@ static int machine__process_ksymbol_register(struct machine *machine,
}
dso__insert_symbol(dso, sym);
out:
- if (put_map)
- map__put(map);
+ map__put(map);
return err;
}
@@ -978,7 +970,7 @@ static int machine__process_ksymbol_unregister(struct machine *machine,
if (sym)
dso__delete_symbol(dso, sym);
}
-
+ map__put(map);
return 0;
}
@@ -1006,11 +998,11 @@ int machine__process_text_poke(struct machine *machine, union perf_event *event,
perf_event__fprintf_text_poke(event, machine, stdout);
if (!event->text_poke.new_len)
- return 0;
+ goto out;
if (cpumode != PERF_RECORD_MISC_KERNEL) {
pr_debug("%s: unsupported cpumode - ignoring\n", __func__);
- return 0;
+ goto out;
}
if (dso) {
@@ -1033,7 +1025,8 @@ int machine__process_text_poke(struct machine *machine, union perf_event *event,
pr_debug("Failed to find kernel text poke address map for %#" PRI_lx64 "\n",
event->text_poke.addr);
}
-
+out:
+ map__put(map);
return 0;
}
@@ -1301,9 +1294,10 @@ static int machine__map_x86_64_entry_trampolines_cb(struct map *map, void *data)
return 0;
dest_map = maps__find(args->kmaps, map__pgoff(map));
- if (dest_map != map)
+ if (RC_CHK_ACCESS(dest_map) != RC_CHK_ACCESS(map))
map__set_pgoff(map, map__map_ip(dest_map, map__pgoff(map)));
+ map__put(dest_map);
args->found = true;
return 0;
}
diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c
index 06fdd8a7c2a2..28facfdac1d7 100644
--- a/tools/perf/util/maps.c
+++ b/tools/perf/util/maps.c
@@ -487,15 +487,18 @@ void maps__remove_maps(struct maps *maps, bool (*cb)(struct map *map, void *data
struct symbol *maps__find_symbol(struct maps *maps, u64 addr, struct map **mapp)
{
struct map *map = maps__find(maps, addr);
+ struct symbol *result = NULL;
/* Ensure map is loaded before using map->map_ip */
if (map != NULL && map__load(map) >= 0) {
- if (mapp != NULL)
- *mapp = map; // TODO: map_put on else path when find returns a get.
- return map__find_symbol(map, map__map_ip(map, addr));
- }
+ if (mapp)
+ *mapp = map;
- return NULL;
+ result = map__find_symbol(map, map__map_ip(map, addr));
+ if (!mapp)
+ map__put(map);
+ }
+ return result;
}
struct maps__find_symbol_by_name_args {
@@ -539,7 +542,7 @@ int maps__find_ams(struct maps *maps, struct addr_map_symbol *ams)
if (ams->addr < map__start(ams->ms.map) || ams->addr >= map__end(ams->ms.map)) {
if (maps == NULL)
return -1;
- ams->ms.map = maps__find(maps, ams->addr); // TODO: map_get
+ ams->ms.map = maps__find(maps, ams->addr);
if (ams->ms.map == NULL)
return -1;
}
@@ -848,7 +851,7 @@ struct map *maps__find(struct maps *maps, u64 ip)
sizeof(*mapp), map__addr_cmp);
if (mapp)
- result = *mapp; // map__get(*mapp);
+ result = map__get(*mapp);
done = true;
}
up_read(maps__lock(maps));
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 30da8a405d11..ad4819a24320 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -757,7 +757,6 @@ static int dso__load_all_kallsyms(struct dso *dso, const char *filename)
static int maps__split_kallsyms_for_kcore(struct maps *kmaps, struct dso *dso)
{
- struct map *curr_map;
struct symbol *pos;
int count = 0;
struct rb_root_cached old_root = dso->symbols;
@@ -770,6 +769,7 @@ static int maps__split_kallsyms_for_kcore(struct maps *kmaps, struct dso *dso)
*root = RB_ROOT_CACHED;
while (next) {
+ struct map *curr_map;
struct dso *curr_map_dso;
char *module;
@@ -796,6 +796,7 @@ static int maps__split_kallsyms_for_kcore(struct maps *kmaps, struct dso *dso)
pos->end -= map__start(curr_map) - map__pgoff(curr_map);
symbols__insert(&curr_map_dso->symbols, pos);
++count;
+ map__put(curr_map);
}
/* Symbols have been adjusted */
--
2.43.0.rc1.413.gea7ed67945-goog