| Message ID | 20230628164611.83038-1-sj@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | [v2] btf: warn but return no error for NULL btf from __register_btf_kfunc_id_set() | expand |
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@ibm.com> > Link: https://lore.kernel.org/bpf/87y228q66f.fsf@oc8242746057.ibm.com/ > Suggested-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> > 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@vger.kernel.org> # 5.18.x > Signed-off-by: SeongJae Park <sj@kernel.org> > Acked-by: Jiri Olsa <jolsa@kernel.org> 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)) >
Hi Daniel, On Fri, 30 Jun 2023 16:53:38 +0200 Daniel Borkmann <daniel@iogearbox.net> 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@ibm.com> > > Link: https://lore.kernel.org/bpf/87y228q66f.fsf@oc8242746057.ibm.com/ > > Suggested-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> > > 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@vger.kernel.org> # 5.18.x > > Signed-off-by: SeongJae Park <sj@kernel.org> > > Acked-by: Jiri Olsa <jolsa@kernel.org> > > 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. > > > 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. Thanks, SJ > > > - 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)) > > > >
On 6/30/23 9:48 PM, SeongJae Park wrote: > On Fri, 30 Jun 2023 16:53:38 +0200 Daniel Borkmann <daniel@iogearbox.net> 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@ibm.com> >>> Link: https://lore.kernel.org/bpf/87y228q66f.fsf@oc8242746057.ibm.com/ >>> Suggested-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> >>> 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@vger.kernel.org> # 5.18.x >>> Signed-off-by: SeongJae Park <sj@kernel.org> >>> Acked-by: Jiri Olsa <jolsa@kernel.org> >> >> 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
On Fri, 30 Jun 2023 22:52:24 +0200 Daniel Borkmann <daniel@iogearbox.net> wrote: > On 6/30/23 9:48 PM, SeongJae Park wrote: > > On Fri, 30 Jun 2023 16:53:38 +0200 Daniel Borkmann <daniel@iogearbox.net> 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@ibm.com> > >>> Link: https://lore.kernel.org/bpf/87y228q66f.fsf@oc8242746057.ibm.com/ > >>> Suggested-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> > >>> 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@vger.kernel.org> # 5.18.x > >>> Signed-off-by: SeongJae Park <sj@kernel.org> > >>> Acked-by: Jiri Olsa <jolsa@kernel.org> > >> > >> 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 >
On 6/30/23 11:02 PM, SeongJae Park wrote: [...] > 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. Perfect, thanks!
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; - } - 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))
__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@ibm.com> Link: https://lore.kernel.org/bpf/87y228q66f.fsf@oc8242746057.ibm.com/ Suggested-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> 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@vger.kernel.org> # 5.18.x Signed-off-by: SeongJae Park <sj@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> --- Changes from v1 (https://lore.kernel.org/all/20230626181120.7086-1-sj@kernel.org/) - Fix Fixes: tag (Jiri Olsa) - Add 'Acked-by: ' from Jiri Olsa kernel/bpf/btf.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-)