On 6/28/23 6:46 PM, SeongJae Park wrote:
__register_btf_kfunc_id_set() assumes .BTF to be part of the module's
.ko file if CONFIG_DEBUG_INFO_BTF is enabled. If that's not the case,
the function prints an error message and return an error. As a result,
such modules cannot be loaded.
However, the section could be stripped out during a build process. It
would be better to let the modules loaded, because their basic
functionalities have no problem[1], though the BTF functionalities will
not be supported. Make the function to lower the level of the message
from error to warn, and return no error.
[1] https://lore.kernel.org/bpf/20220219082037.ow2kbq5brktf4f2u@apollo.legion/
Reported-by: Alexander Egorenkov <Alexander.Egorenkov@xxxxxxx>
Link: https://lore.kernel.org/bpf/87y228q66f.fsf@xxxxxxxxxxxxxxxxxxxx/
Suggested-by: Kumar Kartikeya Dwivedi <memxor@xxxxxxxxx>
Link: https://lore.kernel.org/bpf/20220219082037.ow2kbq5brktf4f2u@apollo.legion/
Fixes: c446fdacb10d ("bpf: fix register_btf_kfunc_id_set for !CONFIG_DEBUG_INFO_BTF")
Cc: <stable@xxxxxxxxxxxxxxx> # 5.18.x
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
I presume this one is targeted at bpf (rather than bpf-next) tree, right?
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 6b682b8e4b50..d683f034996f 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -7848,14 +7848,10 @@ static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook,
btf = btf_get_module_btf(kset->owner);
if (!btf) {
- if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
- pr_err("missing vmlinux BTF, cannot register kfuncs\n");
- return -ENOENT;
- }
Why the above one needs to be changed? Do you also run into this case? vmlinux BTF
should be built-in in this case. I understand it's rather the one below for BTF +
modules instead, no?
- if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
- pr_err("missing module BTF, cannot register kfuncs\n");
- return -ENOENT;
- }
+ if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF))
+ pr_warn("missing vmlinux BTF, cannot register kfuncs\n");
+ if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES))
+ pr_warn("missing module BTF, cannot register kfuncs\n");
return 0;
}
if (IS_ERR(btf))
