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

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

[Xu Jia]

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.

Fixes: 69fd337a975c ("bpf: per-cgroup lsm flavor")
Signed-off-by: Xu Jia <xujia39@huawei.com>
---
 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

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

[Stanislav Fomichev]

On Tue, Jul 19, 2022 at 1:49 AM Xu Jia <xujia39@huawei.com> 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@google.com/

> Fixes: 69fd337a975c ("bpf: per-cgroup lsm flavor")
> Signed-off-by: Xu Jia <xujia39@huawei.com>
> ---
>  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
>

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

[kernel test robot]

Hi Xu,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Xu-Jia/bpf-fix-bpf-compile-error-caused-by-CONFIG_CGROUP_BPF/20220719-165058
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: i386-randconfig-a005-20220718 (https://download.01.org/0day-ci/archive/20220720/202207201518.zmoBBoB6-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project dd5635541cd7bbd62cd59b6694dfb759b6e9a0d8)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/cfd7055cd0be7cfd0de5c24a84c29afe0611cb6c
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Xu-Jia/bpf-fix-bpf-compile-error-caused-by-CONFIG_CGROUP_BPF/20220719-165058
        git checkout cfd7055cd0be7cfd0de5c24a84c29afe0611cb6c
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/ufs/core/ kernel/bpf/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> kernel/bpf/trampoline.c:526:34: warning: unused variable 'bpf_shim_tramp_link_lops' [-Wunused-const-variable]
   static const struct bpf_link_ops bpf_shim_tramp_link_lops = {
                                    ^
   1 warning generated.


vim +/bpf_shim_tramp_link_lops +526 kernel/bpf/trampoline.c

69fd337a975c7e Stanislav Fomichev 2022-06-28  525  
69fd337a975c7e Stanislav Fomichev 2022-06-28 @526  static const struct bpf_link_ops bpf_shim_tramp_link_lops = {
69fd337a975c7e Stanislav Fomichev 2022-06-28  527  	.release = bpf_shim_tramp_link_release,
69fd337a975c7e Stanislav Fomichev 2022-06-28  528  	.dealloc = bpf_shim_tramp_link_dealloc,
69fd337a975c7e Stanislav Fomichev 2022-06-28  529  };
69fd337a975c7e Stanislav Fomichev 2022-06-28  530  

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

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

[xujia (Q)]

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@huawei.com> 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@google.com/
>
>> Fixes: 69fd337a975c ("bpf: per-cgroup lsm flavor")
>> Signed-off-by: Xu Jia <xujia39@huawei.com>
>> ---
>>   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
>>
> .