From 107ef66cb054f8d54e336236a31631a8cc167c1f Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Fri, 9 Feb 2024 19:17:43 -0800 Subject: perf maps: Get map before returning in maps__find_by_name 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 Acked-by: Namhyung Kim Cc: K Prateek Nayak Cc: James Clark Cc: Vincent Whitchurch Cc: Alexey Dobriyan Cc: Colin Ian King Cc: Changbin Du Cc: Masami Hiramatsu Cc: Song Liu Cc: Leo Yan Cc: Athira Rajeev Cc: Liam Howlett Cc: Artem Savkov Cc: bpf@vger.kernel.org Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240210031746.4057262-4-irogers@google.com --- tools/perf/tests/vmlinux-kallsyms.c | 5 +++-- tools/perf/util/machine.c | 6 ++++-- tools/perf/util/maps.c | 6 +++--- tools/perf/util/probe-event.c | 1 + tools/perf/util/symbol-elf.c | 4 +++- tools/perf/util/symbol.c | 18 +++++++++++------- 6 files changed, 25 insertions(+), 15 deletions(-) diff --git a/tools/perf/tests/vmlinux-kallsyms.c b/tools/perf/tests/vmlinux-kallsyms.c index e808e6fc8f76..fecbf851bb2e 100644 --- a/tools/perf/tests/vmlinux-kallsyms.c +++ b/tools/perf/tests/vmlinux-kallsyms.c @@ -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; diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index e8eb9f0b073f..7031f6fddcae 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -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; } diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c index 2547c9074b3a..ea8fa684e8c6 100644 --- a/tools/perf/util/maps.c +++ b/tools/perf/util/maps.c @@ -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; } } diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c index a1a796043691..be71abe8b9b0 100644 --- a/tools/perf/util/probe-event.c +++ b/tools/perf/util/probe-event.c @@ -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); diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c index 95773c32796d..0b91f813c4fa 100644 --- a/tools/perf/util/symbol-elf.c +++ b/tools/perf/util/symbol-elf.c @@ -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; } diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 1710b89e207c..0785a54e832e 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -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; } -- cgit v1.2.3