[PATCH bpf-next 1/2] tools/resolve_btfids: emit warnings and patch zero id for missing symbols
From: Hengqi Chen <hengqi.chen@gmail.com>
Date: 2021-07-25 14:19:02
Subsystem:
bpf [general] (safe dynamic programs and tools), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Kernel functions referenced by .BTF_ids may changed from global to static and get inlined and thus disappears from BTF. This causes kernel build failure when resolve_btfids do id patch for symbols in .BTF_ids in vmlinux. Update resolve_btfids to emit warning messages and patch zero id for missing symbols instead of aborting kernel build process. Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> --- tools/bpf/resolve_btfids/main.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index 3ad9301b0f00..3ea19e33250d 100644
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c@@ -291,7 +291,7 @@ static int compressed_section_fix(Elf *elf, Elf_Scn *scn, GElf_Shdr *sh) sh->sh_addralign = expected; if (gelf_update_shdr(scn, sh) == 0) { - printf("FAILED cannot update section header: %s\n", + pr_err("FAILED cannot update section header: %s\n", elf_errmsg(-1)); return -1; }
@@ -317,6 +317,7 @@ static int elf_collect(struct object *obj) elf = elf_begin(fd, ELF_C_RDWR_MMAP, NULL); if (!elf) { + close(fd); pr_err("FAILED cannot create ELF descriptor: %s\n", elf_errmsg(-1)); return -1;
@@ -484,7 +485,7 @@ static int symbols_resolve(struct object *obj) err = libbpf_get_error(btf); if (err) { pr_err("FAILED: load BTF from %s: %s\n", - obj->path, strerror(-err)); + obj->btf ?: obj->path, strerror(-err)); return -1; }
@@ -555,8 +556,7 @@ static int id_patch(struct object *obj, struct btf_id *id) int i; if (!id->id) { - pr_err("FAILED unresolved symbol %s\n", id->name); - return -EINVAL; + pr_err("WARN: unresolved symbol %s\n", id->name); } for (i = 0; i < id->addr_cnt; i++) {
@@ -734,8 +734,9 @@ int main(int argc, const char **argv) err = 0; out: - if (obj.efile.elf) + if (obj.efile.elf) { elf_end(obj.efile.elf); - close(obj.efile.fd); + close(obj.efile.fd); + } return err; } --
2.25.1