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perf maps: Get map before returning in maps__find_by_name

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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. Also fix some reference counted pointer comparisons.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: James Clark <james.clark@arm.com>
Cc: Vincent Whitchurch <vincent.whitchurch@axis.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Colin Ian King <colin.i.king@gmail.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Artem Savkov <asavkov@redhat.com>
Cc: bpf@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240210031746.4057262-4-irogers@google.com
This commit is contained in:
Ian Rogers 2024-02-09 19:17:43 -08:00 committed by Namhyung Kim
parent 42fd623b58
commit 107ef66cb0
6 changed files with 25 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
tools/perf/tests/vmlinux-kallsyms.c
View File

@ -131,9 +131,10 @@ static int test__vmlinux_matches_kallsyms_cb1(struct map *map, void *data)
struct map *pair = maps__find_by_name(args->kallsyms.kmaps,
(dso->kernel ? dso->short_name : dso->name));
if (pair)
if (pair) {
map__set_priv(pair, 1);
else {
map__put(pair);
} else {
if (!args->header_printed) {
pr_info("WARN: Maps only in vmlinux:\n");
args->header_printed = true;

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

@ -1537,8 +1537,10 @@ static int maps__set_module_path(struct maps *maps, const char *path, struct kmo
return 0;
long_name = strdup(path);
if (long_name == NULL)
if (long_name == NULL) {
map__put(map);
return -ENOMEM;
}
dso = map__dso(map);
dso__set_long_name(dso, long_name, true);
@ -1552,7 +1554,7 @@ static int maps__set_module_path(struct maps *maps, const char *path, struct kmo
dso->symtab_type++;
dso->comp = m->comp;
}
map__put(map);
return 0;
}

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

@ -905,7 +905,7 @@ struct map *maps__find_by_name(struct maps *maps, const char *name)
struct dso *dso = map__dso(maps__maps_by_name(maps)[i]);
if (dso && strcmp(dso->short_name, name) == 0) {
result = maps__maps_by_name(maps)[i]; // TODO: map__get
result = map__get(maps__maps_by_name(maps)[i]);
done = true;
}
}
@ -917,7 +917,7 @@ struct map *maps__find_by_name(struct maps *maps, const char *name)
sizeof(*mapp), map__strcmp_name);
if (mapp) {
result = *mapp; // TODO: map__get
result = map__get(*mapp);
i = mapp - maps__maps_by_name(maps);
RC_CHK_ACCESS(maps)->last_search_by_name_idx = i;
}
@ -942,7 +942,7 @@ struct map *maps__find_by_name(struct maps *maps, const char *name)
struct dso *dso = map__dso(pos);
if (dso && strcmp(dso->short_name, name) == 0) {
result = pos; // TODO: map__get
result = map__get(pos);
break;
}
}

1
tools/perf/util/probe-event.c
View File

@ -358,6 +358,7 @@ static int kernel_get_module_dso(const char *module, struct dso **pdso)
map = maps__find_by_name(machine__kernel_maps(host_machine), module_name);
if (map) {
dso = map__dso(map);
map__put(map);
goto found;
}
pr_debug("Failed to find module %s.\n", module);

4
tools/perf/util/symbol-elf.c
View File

@ -1535,8 +1535,10 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
dso__set_loaded(curr_dso);
*curr_mapp = curr_map;
*curr_dsop = curr_dso;
} else
} else {
*curr_dsop = map__dso(curr_map);
map__put(curr_map);
}
return 0;
}

18
tools/perf/util/symbol.c
View File

@ -814,7 +814,7 @@ static int maps__split_kallsyms(struct maps *kmaps, struct dso *dso, u64 delta,
struct map *initial_map)
{
struct machine *machine;
struct map *curr_map = initial_map;
struct map *curr_map = map__get(initial_map);
struct symbol *pos;
int count = 0, moved = 0;
struct rb_root_cached *root = &dso->symbols;
@ -858,13 +858,14 @@ static int maps__split_kallsyms(struct maps *kmaps, struct dso *dso, u64 delta,
dso__set_loaded(curr_map_dso);
}
map__zput(curr_map);
curr_map = maps__find_by_name(kmaps, module);
if (curr_map == NULL) {
pr_debug("%s/proc/{kallsyms,modules} "
"inconsistency while looking "
"for \"%s\" module!\n",
machine->root_dir, module);
curr_map = initial_map;
curr_map = map__get(initial_map);
goto discard_symbol;
}
curr_map_dso = map__dso(curr_map);
@ -888,7 +889,7 @@ static int maps__split_kallsyms(struct maps *kmaps, struct dso *dso, u64 delta,
* symbols at this point.
*/
goto discard_symbol;
} else if (curr_map != initial_map) {
} else if (!RC_CHK_EQUAL(curr_map, initial_map)) {
char dso_name[PATH_MAX];
struct dso *ndso;
@ -899,7 +900,8 @@ static int maps__split_kallsyms(struct maps *kmaps, struct dso *dso, u64 delta,
}
if (count == 0) {
curr_map = initial_map;
map__zput(curr_map);
curr_map = map__get(initial_map);
goto add_symbol;
}
@ -913,6 +915,7 @@ static int maps__split_kallsyms(struct maps *kmaps, struct dso *dso, u64 delta,
kernel_range++);
ndso = dso__new(dso_name);
map__zput(curr_map);
if (ndso == NULL)
return -1;
@ -926,6 +929,7 @@ static int maps__split_kallsyms(struct maps *kmaps, struct dso *dso, u64 delta,
map__set_mapping_type(curr_map, MAPPING_TYPE__IDENTITY);
if (maps__insert(kmaps, curr_map)) {
map__zput(curr_map);
dso__put(ndso);
return -1;
}
@ -936,7 +940,7 @@ static int maps__split_kallsyms(struct maps *kmaps, struct dso *dso, u64 delta,
pos->end -= delta;
}
add_symbol:
if (curr_map != initial_map) {
if (!RC_CHK_EQUAL(curr_map, initial_map)) {
struct dso *curr_map_dso = map__dso(curr_map);
rb_erase_cached(&pos->rb_node, root);
@ -951,12 +955,12 @@ discard_symbol:
symbol__delete(pos);
}
if (curr_map != initial_map &&
if (!RC_CHK_EQUAL(curr_map, initial_map) &&
dso->kernel == DSO_SPACE__KERNEL_GUEST &&
machine__is_default_guest(maps__machine(kmaps))) {
dso__set_loaded(map__dso(curr_map));
}
map__put(curr_map);
return count + moved;
}