On Wed, Feb 11, 2026 at 05:13:44PM -0800, Ihor Solodrai wrote:
> Running resolve_btfids with ASAN reveals memory leaks in btf_id
> handling.
>
> - Change get_id() to use a local buffer
> - Make btf_id__add() strdup the name internally
> - Add btf_id__free_all() that frees all nodese of a tree
> - Call the cleanup function on exit for every tree
>
> Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Acked-by: Jiri Olsa <jolsa@kernel.org>
one nit below
thanks,
jirka
> ---
> tools/bpf/resolve_btfids/main.c | 78 +++++++++++++++++++++------------
> 1 file changed, 51 insertions(+), 27 deletions(-)
>
> diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
> index ca7fcd03efb6..863fa0faaa31 100644
> --- a/tools/bpf/resolve_btfids/main.c
> +++ b/tools/bpf/resolve_btfids/main.c
> @@ -226,7 +226,7 @@ static struct btf_id *btf_id__find(struct rb_root *root, const char *name)
> }
>
> static struct btf_id *__btf_id__add(struct rb_root *root,
> - char *name,
> + const char *name,
> enum btf_id_kind kind,
> bool unique)
> {
> @@ -250,7 +250,11 @@ static struct btf_id *__btf_id__add(struct rb_root *root,
> id = zalloc(sizeof(*id));
> if (id) {
> pr_debug("adding symbol %s\n", name);
> - id->name = name;
> + id->name = strdup(name);
> + if (!id->name) {
> + free(id);
> + return NULL;
> + }
> id->kind = kind;
> rb_link_node(&id->rb_node, parent, p);
> rb_insert_color(&id->rb_node, root);
> @@ -258,17 +262,17 @@ static struct btf_id *__btf_id__add(struct rb_root *root,
> return id;
> }
>
> -static inline struct btf_id *btf_id__add(struct rb_root *root, char *name, enum btf_id_kind kind)
> +static inline struct btf_id *btf_id__add(struct rb_root *root, const char *name, enum btf_id_kind kind)
> {
> return __btf_id__add(root, name, kind, false);
> }
>
> -static inline struct btf_id *btf_id__add_unique(struct rb_root *root, char *name, enum btf_id_kind kind)
> +static inline struct btf_id *btf_id__add_unique(struct rb_root *root, const char *name, enum btf_id_kind kind)
> {
> return __btf_id__add(root, name, kind, true);
> }
>
> -static char *get_id(const char *prefix_end)
> +static int get_id(const char *prefix_end, char *buf, size_t buf_sz)
> {
> /*
> * __BTF_ID__func__vfs_truncate__0
> @@ -277,28 +281,28 @@ static char *get_id(const char *prefix_end)
> */
> int len = strlen(prefix_end);
> int pos = sizeof("__") - 1;
> - char *p, *id;
> + char *p;
>
> if (pos >= len)
> - return NULL;
> + return -1;
>
> - id = strdup(prefix_end + pos);
> - if (id) {
> - /*
> - * __BTF_ID__func__vfs_truncate__0
> - * id = ^
> - *
> - * cut the unique id part
> - */
> - p = strrchr(id, '_');
> - p--;
> - if (*p != '_') {
> - free(id);
> - return NULL;
> - }
> - *p = '\0';
> - }
> - return id;
> + if (len - pos >= buf_sz)
> + return -1;
> +
> + strcpy(buf, prefix_end + pos);
> + /*
> + * __BTF_ID__func__vfs_truncate__0
> + * buf = ^
> + *
> + * cut the unique id part
> + */
> + p = strrchr(buf, '_');
> + p--;
> + if (*p != '_')
> + return -1;
> + *p = '\0';
> +
> + return 0;
> }
>
> static struct btf_id *add_set(struct object *obj, char *name, enum btf_id_kind kind)
> @@ -335,10 +339,9 @@ static struct btf_id *add_set(struct object *obj, char *name, enum btf_id_kind k
>
> static struct btf_id *add_symbol(struct rb_root *root, char *name, size_t size)
> {
> - char *id;
> + char id[KSYM_NAME_LEN];
>
> - id = get_id(name + size);
> - if (!id) {
> + if (get_id(name + size, id, sizeof(id))) {
> pr_err("FAILED to parse symbol name: %s\n", name);
> return NULL;
> }
> @@ -346,6 +349,22 @@ static struct btf_id *add_symbol(struct rb_root *root, char *name, size_t size)
> return btf_id__add(root, id, BTF_ID_KIND_SYM);
> }
>
> +static void btf_id__free_all(struct rb_root *root)
> +{
> + struct rb_node *node, *next;
> + struct btf_id *id;
> +
> + node = rb_first(root);
> + while (node) {
> + next = rb_next(node);
> + id = rb_entry(node, struct btf_id, rb_node);
> + rb_erase(node, root);
> + free(id->name);
> + free(id);
> + node = next;
> + }
> +}
nit, I think we could do it with just single rb_node pointer, like:
next = rb_first(root);
while (next) {
id = rb_entry(next, struct btf_id, rb_node);
next = rb_next(&id->rb_node);
rb_erase(&id->rb_node, root);
free(id->name);
free(id);
}
jirka
> +
> static void bswap_32_data(void *data, u32 nr_bytes)
> {
> u32 cnt, i;
> @@ -1547,6 +1566,11 @@ int main(int argc, const char **argv)
> out:
> btf__free(obj.base_btf);
> btf__free(obj.btf);
> + btf_id__free_all(&obj.structs);
> + btf_id__free_all(&obj.unions);
> + btf_id__free_all(&obj.typedefs);
> + btf_id__free_all(&obj.funcs);
> + btf_id__free_all(&obj.sets);
> if (obj.efile.elf) {
> elf_end(obj.efile.elf);
> close(obj.efile.fd);
> --
> 2.53.0
>
>