The kernel image can contain multiple types (structs/unions) with the same name. This causes distinct type hierarchies in BTF data and makes resolve_btfids fail with error like: BTFIDS vmlinux FAILED unresolved symbol udp6_sock as reported by Qais Yousef [1]. This change adds warning when multiple types of the same name are detected: BTFIDS vmlinux WARN: multiple IDs found for 'file': 526, 113351 - using 526 WARN: multiple IDs found for 'sk_buff': 2744, 113958 - using 2744 We keep the lower ID for the given type instance and let the build continue. Also changing the 'nr' variable name to 'nr_types' to avoid confusion. [1] https://lore.kernel.org/lkml/20201229151352.6hzmjvu3qh6p2qgg@e107158-lin/ Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx> --- v2 changes: - changed the warning message [Alexei] - renamed 'nr' to 'nr_types' [Andrii] tools/bpf/resolve_btfids/main.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c index e3ea569ee125..7409d7860aa6 100644 --- a/tools/bpf/resolve_btfids/main.c +++ b/tools/bpf/resolve_btfids/main.c @@ -139,6 +139,8 @@ int eprintf(int level, int var, const char *fmt, ...) #define pr_debug2(fmt, ...) pr_debugN(2, pr_fmt(fmt), ##__VA_ARGS__) #define pr_err(fmt, ...) \ eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__) +#define pr_info(fmt, ...) \ + eprintf(0, verbose, pr_fmt(fmt), ##__VA_ARGS__) static bool is_btf_id(const char *name) { @@ -472,7 +474,7 @@ static int symbols_resolve(struct object *obj) int nr_funcs = obj->nr_funcs; int err, type_id; struct btf *btf; - __u32 nr; + __u32 nr_types; btf = btf__parse(obj->btf ?: obj->path, NULL); err = libbpf_get_error(btf); @@ -483,12 +485,12 @@ static int symbols_resolve(struct object *obj) } err = -1; - nr = btf__get_nr_types(btf); + nr_types = btf__get_nr_types(btf); /* * Iterate all the BTF types and search for collected symbol IDs. */ - for (type_id = 1; type_id <= nr; type_id++) { + for (type_id = 1; type_id <= nr_types; type_id++) { const struct btf_type *type; struct rb_root *root; struct btf_id *id; @@ -526,8 +528,13 @@ static int symbols_resolve(struct object *obj) id = btf_id__find(root, str); if (id) { - id->id = type_id; - (*nr)--; + if (id->id) { + pr_info("WARN: multiple IDs found for '%s': %d, %d - using %d\n", + str, id->id, type_id, id->id); + } else { + id->id = type_id; + (*nr)--; + } } } -- 2.26.2
