Re: [PATCH bpf-next] bpf: fix bpf compile error caused by CONFIG_CGROUP_BPF

["xujia (Q)" <xujia39@xxxxxxxxxx>]

It is fixed, not warning again. Thank you very much!

在 2022/7/19 23:46, Stanislav Fomichev 写道:
> On Tue, Jul 19, 2022 at 1:49 AM Xu Jia <xujia39@xxxxxxxxxx> wrote:
> > We failed to compile when CONFIG_BPF_LSM is enabled but CONFIG_CGROUP_BPF
> > is not set. The failings are shown as below:
> >
> > kernel/bpf/trampoline.o: in function `bpf_trampoline_link_cgroup_shim'
> > trampoline.c: undefined reference to `bpf_cgroup_atype_get'
> > kernel/bpf/bpf_lsm.o: In function `bpf_lsm_find_cgroup_shim':
> > bpf_lsm.c: undefined reference to `__cgroup_bpf_run_lsm_current'
> > bpf_lsm.c: undefined reference to `__cgroup_bpf_run_lsm_sock'
> > bpf_lsm.c: undefined reference to `__cgroup_bpf_run_lsm_socket'
> >
> > Fix them by protecting these functions with CONFIG_CGROUP_BPF.
> Should be fixed by the following?
>
> https://lore.kernel.org/bpf/20220714185404.3647772-1-sdf@xxxxxxxxxx/
>
> > Fixes: 69fd337a975c ("bpf: per-cgroup lsm flavor")
> > Signed-off-by: Xu Jia <xujia39@xxxxxxxxxx>
> > ---
> >   include/linux/bpf.h     | 12 +++++++++---
> >   include/linux/bpf_lsm.h | 10 ++++++----
> >   kernel/bpf/bpf_lsm.c    |  2 ++
> >   kernel/bpf/trampoline.c |  2 ++
> >   4 files changed, 19 insertions(+), 7 deletions(-)
> >
> > diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> > index 2b21f2a3452f..add8895c02cc 100644
> > --- a/include/linux/bpf.h
> > +++ b/include/linux/bpf.h
> > @@ -1255,9 +1255,7 @@ struct bpf_dummy_ops {
> >   int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr,
> >                              union bpf_attr __user *uattr);
> >   #endif
> > -int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
> > -                                   int cgroup_atype);
> > -void bpf_trampoline_unlink_cgroup_shim(struct bpf_prog *prog);
> > +
> >   #else
> >   static inline const struct bpf_struct_ops *bpf_struct_ops_find(u32 type_id)
> >   {
> > @@ -1281,6 +1279,14 @@ static inline int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map,
> >   {
> >          return -EINVAL;
> >   }
> > +#endif
> > +
> > +#if defined(CONFIG_BPF_JIT) && defined(CONFIG_BPF_SYSCALL) && \
> > +    defined(CONFIG_CGROUP_BPF)
> > +int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
> > +                                   int cgroup_atype);
> > +void bpf_trampoline_unlink_cgroup_shim(struct bpf_prog *prog);
> > +#else
> >   static inline int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
> >                                                    int cgroup_atype)
> >   {
> > diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h
> > index 4bcf76a9bb06..bed45a0c8a9c 100644
> > --- a/include/linux/bpf_lsm.h
> > +++ b/include/linux/bpf_lsm.h
> > @@ -42,8 +42,6 @@ extern const struct bpf_func_proto bpf_inode_storage_get_proto;
> >   extern const struct bpf_func_proto bpf_inode_storage_delete_proto;
> >   void bpf_inode_storage_free(struct inode *inode);
> >
> > -void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog, bpf_func_t *bpf_func);
> > -
> >   #else /* !CONFIG_BPF_LSM */
> >
> >   static inline bool bpf_lsm_is_sleepable_hook(u32 btf_id)
> > @@ -67,11 +65,15 @@ static inline void bpf_inode_storage_free(struct inode *inode)
> >   {
> >   }
> >
> > +#endif /* CONFIG_BPF_LSM */
> > +
> > +#if defined(CONFIG_BPF_LSM) && defined(CONFIG_BPF_CGROUP)
> > +void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog, bpf_func_t *bpf_func);
> > +#else
> >   static inline void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog,
> >                                             bpf_func_t *bpf_func)
> >   {
> >   }
> > -
> > -#endif /* CONFIG_BPF_LSM */
> > +#endif
> >
> >   #endif /* _LINUX_BPF_LSM_H */
> > diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c
> > index d469b7f3deef..29527828b38b 100644
> > --- a/kernel/bpf/bpf_lsm.c
> > +++ b/kernel/bpf/bpf_lsm.c
> > @@ -63,6 +63,7 @@ BTF_ID(func, bpf_lsm_socket_post_create)
> >   BTF_ID(func, bpf_lsm_socket_socketpair)
> >   BTF_SET_END(bpf_lsm_unlocked_sockopt_hooks)
> >
> > +#ifdef CONFIG_BPF_CGROUP
> >   void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog,
> >                               bpf_func_t *bpf_func)
> >   {
> > @@ -86,6 +87,7 @@ void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog,
> >   #endif
> >                  *bpf_func = __cgroup_bpf_run_lsm_current;
> >   }
> > +#endif /* CONFIG_BPF_CGROUP */
> >
> >   int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog,
> >                          const struct bpf_prog *prog)
> > diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
> > index 6cd226584c33..127924711935 100644
> > --- a/kernel/bpf/trampoline.c
> > +++ b/kernel/bpf/trampoline.c
> > @@ -525,6 +525,7 @@ static const struct bpf_link_ops bpf_shim_tramp_link_lops = {
> >          .dealloc = bpf_shim_tramp_link_dealloc,
> >   };
> >
> > +#ifdef CONFIG_CGROUP_BPF
> >   static struct bpf_shim_tramp_link *cgroup_shim_alloc(const struct bpf_prog *prog,
> >                                                       bpf_func_t bpf_func,
> >                                                       int cgroup_atype)
> > @@ -668,6 +669,7 @@ void bpf_trampoline_unlink_cgroup_shim(struct bpf_prog *prog)
> >
> >          bpf_trampoline_put(tr); /* bpf_trampoline_lookup above */
> >   }
> > +#endif /* CONFIG_CGROUP_BPF */
> >   #endif
> >
> >   struct bpf_trampoline *bpf_trampoline_get(u64 key,
> > --
> > 2.25.1
> .