On 6/30/23 9:48 PM, SeongJae Park wrote:
On Fri, 30 Jun 2023 16:53:38 +0200 Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
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?
You're correct. It's not urgent for us, but I would prefer it to be merged
into all affected kernels as early as possible.
Ok, sounds good, bpf tree it is then.
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?
Again, you're correct. This change is not really needed. I was interpreting
Kumar's suggestion merely into code without thinking about his real meaning,
sorry. I will restore this in the next spin.
Perfect, I think after your v3 respin it should be good to land.
Thanks,
Daniel
