On Fri, 30 Jun 2023 22:52:24 +0200 Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote: > 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. Thank you! I will send it by tomorrow, to give people enough time to comment. If you don't want to wait, please let me know :) Also, please note that this will not cleanly applicable on 6.1.y. I will provide the backport to stable@ as soon as this is merged into the mainline. Thanks, SJ > > Thanks, > Daniel >
