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 >
