On Mon, Sep 14, 2020 at 10:48:36AM -0400, Veronika Kabatova wrote:
>
> Hello,
>
> we tested the bpf-next tree with CKI and ran across build failures. The
> important part of the build log is:
>
> 00:18:05 GEN .version
> 00:18:05 CHK include/generated/compile.h
> 00:18:05 LD vmlinux.o
> 00:18:27 MODPOST vmlinux.symvers
> 00:18:27 MODINFO modules.builtin.modinfo
> 00:18:27 GEN modules.builtin
> 00:18:27 LD .tmp_vmlinux.btf
> 00:18:42 BTF .btf.vmlinux.bin.o
> 00:19:13 LD .tmp_vmlinux.kallsyms1
> 00:19:19 KSYM .tmp_vmlinux.kallsyms1.o
> 00:19:22 LD .tmp_vmlinux.kallsyms2
> 00:19:25 KSYM .tmp_vmlinux.kallsyms2.o
> 00:19:28 LD vmlinux
> 00:19:40 BTFIDS vmlinux
> 00:19:40 FAILED unresolved symbol vfs_getattr
> 00:19:40 make[2]: *** [Makefile:1167: vmlinux] Error 255
> 00:19:40 make[1]: *** [scripts/Makefile.package:109: targz-pkg] Error 2
> 00:19:40 make: *** [Makefile:1528: targz-pkg] Error 2
hi,
it looks like broken BTF data to me, I checked that build
and found we have multiple records for functions, like
for filp_close:
[23381] FUNC_PROTO '(anon)' ret_type_id=19 vlen=2
'(anon)' type_id=464
'id' type_id=960
[23382] FUNC 'filp_close' type_id=23381 linkage=static
[33073] FUNC_PROTO '(anon)' ret_type_id=19 vlen=2
'filp' type_id=464
'id' type_id=960
[33074] FUNC 'filp_close' type_id=33073 linkage=static
or vfs_getattr:
[33513] FUNC_PROTO '(anon)' ret_type_id=19 vlen=4
'path' type_id=741
'stat' type_id=1095
'request_mask' type_id=29
'query_flags' type_id=8
[33514] FUNC 'vfs_getattr' type_id=33513 linkage=static
[1094] FUNC_PROTO '(anon)' ret_type_id=19 vlen=4
'(anon)' type_id=741
'(anon)' type_id=1095
'(anon)' type_id=29
'(anon)' type_id=8
[35099] FUNC 'vfs_getattr' type_id=1094 linkage=static
and because we go through all BTF data until we resolve all we have,
the doubled funcs will screw our internal counter and we skip a function
the change below will workaround that, but I think we should fail in
this case.. if I'm not missing something 2 FUNC records for one function
in BTF data
$ pahole --version
v1.17
HEAD is 2bab48c5b Merge branch 'improve-bpf-tcp-cc-init'
thoughts? thanks
jirka
---
diff --git a/tools/bpf/resolve_btfids/main.c b/tools/bpf/resolve_btfids/main.c
index dfa540d8a02d..a33e56553e52 100644
--- a/tools/bpf/resolve_btfids/main.c
+++ b/tools/bpf/resolve_btfids/main.c
@@ -525,7 +525,7 @@ static int symbols_resolve(struct object *obj)
}
id = btf_id__find(root, str);
- if (id) {
+ if (id && !id->id) {
id->id = type_id;
(*nr)--;
}
