1 files changed, 149 insertions, 57 deletions

diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c
index 4092211cff62..f808df2fe77b 100644
--- a/tools/perf/util/maps.c
+++ b/tools/perf/util/maps.c
@@ -40,6 +40,7 @@ DECLARE_RC_STRUCT(maps) {
 #ifdef HAVE_LIBUNWIND_SUPPORT
 	void		*addr_space;
 	const struct unwind_libunwind_ops *unwind_libunwind_ops;
+	uint16_t	 e_machine;
 #endif
 #ifdef HAVE_LIBDW_SUPPORT
 	void		*libdw_addr_space_dwfl;
@@ -197,14 +198,14 @@ void maps__set_addr_space(struct maps *maps, void *addr_space)
 	RC_CHK_ACCESS(maps)->addr_space = addr_space;
 }
 
-const struct unwind_libunwind_ops *maps__unwind_libunwind_ops(const struct maps *maps)
+uint16_t maps__e_machine(const struct maps *maps)
 {
-	return RC_CHK_ACCESS(maps)->unwind_libunwind_ops;
+	return RC_CHK_ACCESS(maps)->e_machine;
 }
 
-void maps__set_unwind_libunwind_ops(struct maps *maps, const struct unwind_libunwind_ops *ops)
+void maps__set_e_machine(struct maps *maps, uint16_t e_machine)
 {
-	RC_CHK_ACCESS(maps)->unwind_libunwind_ops = ops;
+	RC_CHK_ACCESS(maps)->e_machine = e_machine;
 }
 #endif
 #ifdef HAVE_LIBDW_SUPPORT
@@ -575,6 +576,48 @@ void maps__remove(struct maps *maps, struct map *map)
 #endif
 }
 
+/**
+ * maps__mutate_mapping - Apply write-protected mutations to a map.
+ * @maps: The maps collection containing the map.
+ * @map: The map to mutate.
+ * @mutate_cb: Callback function that performs the actual mutations.
+ * @data: Private data passed to the callback.
+ *
+ * This acquires the write lock on the maps semaphore to safely protect
+ * concurrent readers from seeing partially mutated or unsorted map boundaries.
+ *
+ * WARNING: Acquiring down_write() here can trigger a recursive self-deadlock if
+ * the caller already holds the read lock (e.g., during maps__for_each_map() or
+ * maps__find() iteration paths that trigger lazy symbol loading). To completely
+ * avoid this deadlock, all kernel/module maps must be pre-loaded up-front (via
+ * maps__load_maps()) under a clean, single-threaded context before entering
+ * multi-threaded event processing loops.
+ */
+int maps__mutate_mapping(struct maps *maps, struct map *map,
+			 int (*mutate_cb)(struct map *map, void *data), void *data)
+{
+	int err = 0;
+
+	if (maps) {
+		down_write(maps__lock(maps));
+
+		err = mutate_cb(map, data);
+
+		RC_CHK_ACCESS(maps)->maps_by_address_sorted = false;
+		RC_CHK_ACCESS(maps)->maps_by_name_sorted = false;
+
+		up_write(maps__lock(maps));
+
+#ifdef HAVE_LIBDW_SUPPORT
+		libdw__invalidate_dwfl(maps, maps__libdw_addr_space_dwfl(maps));
+#endif
+	} else {
+		err = mutate_cb(map, data);
+	}
+
+	return err;
+}
+
 bool maps__empty(struct maps *maps)
 {
 	bool res;
@@ -625,6 +668,41 @@ int maps__for_each_map(struct maps *maps, int (*cb)(struct map *map, void *data)
 	return ret;
 }
 
+int maps__load_maps(struct maps *maps)
+{
+	struct map **maps_copy;
+	unsigned int nr_maps;
+	int err = 0;
+
+	if (!maps)
+		return 0;
+
+	down_read(maps__lock(maps));
+	nr_maps = maps__nr_maps(maps);
+	if (nr_maps == 0) {
+		up_read(maps__lock(maps));
+		return 0;
+	}
+	maps_copy = calloc(nr_maps, sizeof(*maps_copy));
+	if (!maps_copy) {
+		up_read(maps__lock(maps));
+		return -ENOMEM;
+	}
+	for (unsigned int i = 0; i < nr_maps; i++)
+		maps_copy[i] = map__get(maps__maps_by_address(maps)[i]);
+	up_read(maps__lock(maps));
+
+	for (unsigned int i = 0; i < nr_maps; i++) {
+		if (map__load(maps_copy[i]) < 0) {
+			pr_warning("Failed to load map %s\n", dso__name(map__dso(maps_copy[i])));
+			err = -1;
+		}
+		map__put(maps_copy[i]);
+	}
+	free(maps_copy);
+	return err;
+}
+
 void maps__remove_maps(struct maps *maps, bool (*cb)(struct map *map, void *data), void *data)
 {
 	struct map **maps_by_address;
@@ -667,40 +745,57 @@ struct symbol *maps__find_symbol(struct maps *maps, u64 addr, struct map **mapp)
 	return result;
 }
 
-struct maps__find_symbol_by_name_args {
-	struct map **mapp;
-	const char *name;
-	struct symbol *sym;
-};
-
-static int maps__find_symbol_by_name_cb(struct map *map, void *data)
+struct symbol *maps__find_symbol_by_name(struct maps *maps, const char *name, struct map **mapp)
 {
-	struct maps__find_symbol_by_name_args *args = data;
+	struct map **maps_copy;
+	unsigned int nr_maps;
+	struct symbol *sym = NULL;
 
-	args->sym = map__find_symbol_by_name(map, args->name);
-	if (!args->sym)
-		return 0;
+	if (!maps)
+		return NULL;
 
-	if (!map__contains_symbol(map, args->sym)) {
-		args->sym = NULL;
-		return 0;
+	/*
+	 * First, ensure all maps are loaded. We pre-load them outside of any
+	 * read-to-write locks to avoid deadlocks. Even if some fail, we proceed.
+	 */
+	maps__load_maps(maps);
+
+	/*
+	 * Create a local snapshot of the maps while holding the read lock.
+	 * This prevents deadlocking if iteration triggers further map insertions.
+	 */
+	down_read(maps__lock(maps));
+	nr_maps = maps__nr_maps(maps);
+	maps_copy = calloc(nr_maps, sizeof(*maps_copy));
+	if (maps_copy) {
+		for (unsigned int i = 0; i < nr_maps; i++) {
+			struct map *map = maps__maps_by_address(maps)[i];
+
+			maps_copy[i] = map__get(map);
+		}
 	}
+	up_read(maps__lock(maps));
 
-	if (args->mapp != NULL)
-		*args->mapp = map__get(map);
-	return 1;
-}
+	if (!maps_copy)
+		return NULL;
 
-struct symbol *maps__find_symbol_by_name(struct maps *maps, const char *name, struct map **mapp)
-{
-	struct maps__find_symbol_by_name_args args = {
-		.mapp = mapp,
-		.name = name,
-		.sym = NULL,
-	};
+	for (unsigned int i = 0; i < nr_maps; i++) {
+		struct map *map = maps_copy[i];
+
+		sym = map__find_symbol_by_name(map, name);
+		if (sym && map__contains_symbol(map, sym)) {
+			if (mapp)
+				*mapp = map__get(map);
+			break;
+		}
+		sym = NULL;
+	}
 
-	maps__for_each_map(maps, maps__find_symbol_by_name_cb, &args);
-	return args.sym;
+	for (unsigned int i = 0; i < nr_maps; i++)
+		map__put(maps_copy[i]);
+
+	free(maps_copy);
+	return sym;
 }
 
 int maps__find_ams(struct maps *maps, struct addr_map_symbol *ams)
@@ -844,7 +939,6 @@ static int __maps__insert_sorted(struct maps *maps, unsigned int first_after_ind
 static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 {
 	int err = 0;
-	FILE *fp = debug_file();
 	unsigned int i, ni = INT_MAX; // Some gcc complain, but depends on maps_by_name...
 
 	if (!maps__maps_by_address_sorted(maps))
@@ -872,8 +966,8 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 				dso__name(map__dso(new)));
 		} else if (verbose >= 2) {
 			pr_debug("overlapping maps:\n");
-			map__fprintf(new, fp);
-			map__fprintf(pos, fp);
+			map__fprintf(new, debug_file());
+			map__fprintf(pos, debug_file());
 		}
 
 		if (maps_by_name)
@@ -894,7 +988,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 			map__set_end(before, map__start(new));
 
 			if (verbose >= 2 && !use_browser)
-				map__fprintf(before, fp);
+				map__fprintf(before, debug_file());
 		}
 		if (map__end(new) < map__end(pos)) {
 			/* The new map isn't as long as the existing map. */
@@ -912,7 +1006,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 			       map__map_ip(after, map__end(new)));
 
 			if (verbose >= 2 && !use_browser)
-				map__fprintf(after, fp);
+				map__fprintf(after, debug_file());
 		}
 		/*
 		 * If adding one entry, for `before` or `after`, we can replace
@@ -956,6 +1050,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 			if (maps_by_name) {
 				map__put(maps_by_name[ni]);
 				maps_by_name[ni] = map__get(new);
+				maps__set_maps_by_name_sorted(maps, false);
 			}
 
 			err = __maps__insert_sorted(maps, i + 1, after, NULL);
@@ -982,6 +1077,7 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new)
 				if (maps_by_name) {
 					map__put(maps_by_name[ni]);
 					maps_by_name[ni] = map__get(new);
+					maps__set_maps_by_name_sorted(maps, false);
 				}
 
 				check_invariants(maps);
@@ -1038,6 +1134,14 @@ int maps__copy_from(struct maps *dest, struct maps *parent)
 	down_write(maps__lock(dest));
 	down_read(maps__lock(parent));
 
+#ifdef HAVE_LIBUNWIND_SUPPORT
+	err = unwind__prepare_access(dest, maps__e_machine(parent));
+	if (err) {
+		up_read(maps__lock(parent));
+		up_write(maps__lock(dest));
+		return err;
+	}
+#endif
 	parent_maps_by_address = maps__maps_by_address(parent);
 	n = maps__nr_maps(parent);
 	if (maps__nr_maps(dest) == 0) {
@@ -1067,29 +1171,19 @@ int maps__copy_from(struct maps *dest, struct maps *parent)
 			if (!new)
 				err = -ENOMEM;
 			else {
-				err = unwind__prepare_access(dest, new, NULL);
-				if (!err) {
-					dest_maps_by_address[i] = new;
-					map__set_kmap_maps(new, dest);
-					if (dest_maps_by_name)
-						dest_maps_by_name[i] = map__get(new);
-					RC_CHK_ACCESS(dest)->nr_maps = i + 1;
-				}
+				dest_maps_by_address[i] = new;
+				map__set_kmap_maps(new, dest);
+				if (dest_maps_by_name)
+					dest_maps_by_name[i] = map__get(new);
+				RC_CHK_ACCESS(dest)->nr_maps = i + 1;
 			}
 			if (err)
 				map__put(new);
 		}
 		maps__set_maps_by_address_sorted(dest, maps__maps_by_address_sorted(parent));
-		if (!err) {
-			RC_CHK_ACCESS(dest)->last_search_by_name_idx =
-				RC_CHK_ACCESS(parent)->last_search_by_name_idx;
-			maps__set_maps_by_name_sorted(dest,
-						dest_maps_by_name &&
-						maps__maps_by_name_sorted(parent));
-		} else {
-			RC_CHK_ACCESS(dest)->last_search_by_name_idx = 0;
-			maps__set_maps_by_name_sorted(dest, false);
-		}
+		RC_CHK_ACCESS(dest)->last_search_by_name_idx = 0;
+		/* Values were copied into the name array in address order. */
+		maps__set_maps_by_name_sorted(dest, false);
 	} else {
 		/* Unexpected copying to a maps containing entries. */
 		for (unsigned int i = 0; !err && i < n; i++) {
@@ -1099,9 +1193,7 @@ int maps__copy_from(struct maps *dest, struct maps *parent)
 			if (!new)
 				err = -ENOMEM;
 			else {
-				err = unwind__prepare_access(dest, new, NULL);
-				if (!err)
-					err = __maps__insert(dest, new);
+				err = __maps__insert(dest, new);
 			}
 			map__put(new);
 		}