From: Hengqi Chen <hengqi.chen@gmail.com>
Date: Tue, 27 Jul 2021 21:25:31 +0800
Subject: tools/resolve_btfids: Emit warnings and patch zero id for missing
symbols
Patch-mainline: v5.15-rc1
Git-commit: 5aad03685185b5133a28e1ee1d4e98d3fd3642a3
References: jsc#PED-1377
Kernel functions referenced by .BTF_ids may be changed from global to static
and get inlined or get renamed/removed, 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.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20210727132532.2473636-2-hengqi.chen@gmail.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
tools/bpf/resolve_btfids/main.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -291,7 +291,7 @@ static int compressed_section_fix(Elf *e
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 *ob
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
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,
int i;
if (!id->id) {
- pr_err("FAILED unresolved symbol %s\n", id->name);
- return -EINVAL;
+ pr_err("WARN: resolve_btfids: 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;
}