[PATCH bpf-next v2] bpftool: Add support for custom BTF path in prog load/loadall

[PATCH bpf-next v2] bpftool: Add support for custom BTF path in prog load/loadall

[Jiayuan Chen]

This patch exposes the btf_custom_path feature to bpftool, allowing users
to specify a custom BTF file when loading BPF programs using prog load or
prog loadall commands.

The argument 'btf_custom_path' in libbpf is used for those kernes that
don't have CONFIG_DEBUG_INFO_BTF enabled but still want to perform CO-RE
relocations.

Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
---
 tools/bpf/bpftool/Documentation/bpftool-prog.rst |  7 ++++++-
 tools/bpf/bpftool/bash-completion/bpftool        |  2 +-
 tools/bpf/bpftool/prog.c                         | 12 +++++++++++-
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
index d6304e01afe0..e60a829ab8d0 100644
--- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
+++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
@@ -127,7 +127,7 @@ bpftool prog pin *PROG* *FILE*
     Note: *FILE* must be located in *bpffs* mount. It must not contain a dot
     character ('.'), which is reserved for future extensions of *bpffs*.
 
-bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | name *NAME* } *MAP*] [{ offload_dev | xdpmeta_dev } *NAME*] [pinmaps *MAP_DIR*] [autoattach]
+bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | name *NAME* } *MAP*] [{ offload_dev | xdpmeta_dev } *NAME*] [pinmaps *MAP_DIR*] [autoattach] [kernel_btf *BTF_DIR*]
     Load bpf program(s) from binary *OBJ* and pin as *PATH*. **bpftool prog
     load** pins only the first program from the *OBJ* as *PATH*. **bpftool prog
     loadall** pins all programs from the *OBJ* under *PATH* directory. **type**
@@ -153,6 +153,11 @@ bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | na
     program does not support autoattach, bpftool falls back to regular pinning
     for that program instead.
 
+    The **kernel_btf** option allows specifying an external BTF file to replace
+    the system's own vmlinux BTF file for CO-RE relocations. NOTE that any
+    other feature (e.g., fentry/fexit programs, struct_ops, etc) will require
+    actual kernel BTF like /sys/kernel/btf/vmlinux.
+
     Note: *PATH* must be located in *bpffs* mount. It must not contain a dot
     character ('.'), which is reserved for future extensions of *bpffs*.
 
diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
index 1ce409a6cbd9..609938c287b7 100644
--- a/tools/bpf/bpftool/bash-completion/bpftool
+++ b/tools/bpf/bpftool/bash-completion/bpftool
@@ -511,7 +511,7 @@ _bpftool()
                             ;;
                         *)
                             COMPREPLY=( $( compgen -W "map" -- "$cur" ) )
-                            _bpftool_once_attr 'type pinmaps autoattach'
+                            _bpftool_once_attr 'type pinmaps autoattach kernel_btf'
                             _bpftool_one_of_list 'offload_dev xdpmeta_dev'
                             return 0
                             ;;
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index f010295350be..3b6a361dd0f8 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -1681,8 +1681,17 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
 		} else if (is_prefix(*argv, "autoattach")) {
 			auto_attach = true;
 			NEXT_ARG();
+		} else if (is_prefix(*argv, "kernel_btf")) {
+			NEXT_ARG();
+
+			if (!REQ_ARGS(1))
+				goto err_free_reuse_maps;
+
+			open_opts.btf_custom_path = GET_ARG();
 		} else {
-			p_err("expected no more arguments, 'type', 'map' or 'dev', got: '%s'?",
+			p_err("expected no more arguments, "
+			      "'type', 'map', 'dev', 'offload_dev', 'xdpmeta_dev', 'pinmaps', "
+			      "'autoattach', or 'kernel_btf', got: '%s'?",
 			      *argv);
 			goto err_free_reuse_maps;
 		}
@@ -2474,6 +2483,7 @@ static int do_help(int argc, char **argv)
 		"                         [map { idx IDX | name NAME } MAP]\\\n"
 		"                         [pinmaps MAP_DIR]\n"
 		"                         [autoattach]\n"
+		"                         [kernel_btf BTF_DIR]\n"
 		"       %1$s %2$s attach PROG ATTACH_TYPE [MAP]\n"
 		"       %1$s %2$s detach PROG ATTACH_TYPE [MAP]\n"
 		"       %1$s %2$s run PROG \\\n"
-- 
2.47.1

Re: [PATCH bpf-next v2] bpftool: Add support for custom BTF path in prog load/loadall

[Quentin Monnet]

2025-05-15 14:50 UTC+0800 ~ Jiayuan Chen <jiayuan.chen@linux.dev>
> This patch exposes the btf_custom_path feature to bpftool, allowing users
> to specify a custom BTF file when loading BPF programs using prog load or
> prog loadall commands.
> 
> The argument 'btf_custom_path' in libbpf is used for those kernes that


Typo: "kernes"


> don't have CONFIG_DEBUG_INFO_BTF enabled but still want to perform CO-RE
> relocations.
> 
> Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
> ---
>  tools/bpf/bpftool/Documentation/bpftool-prog.rst |  7 ++++++-
>  tools/bpf/bpftool/bash-completion/bpftool        |  2 +-
>  tools/bpf/bpftool/prog.c                         | 12 +++++++++++-
>  3 files changed, 18 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
> index d6304e01afe0..e60a829ab8d0 100644
> --- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
> +++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
> @@ -127,7 +127,7 @@ bpftool prog pin *PROG* *FILE*
>      Note: *FILE* must be located in *bpffs* mount. It must not contain a dot
>      character ('.'), which is reserved for future extensions of *bpffs*.
>  
> -bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | name *NAME* } *MAP*] [{ offload_dev | xdpmeta_dev } *NAME*] [pinmaps *MAP_DIR*] [autoattach]
> +bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | name *NAME* } *MAP*] [{ offload_dev | xdpmeta_dev } *NAME*] [pinmaps *MAP_DIR*] [autoattach] [kernel_btf *BTF_DIR*]
>      Load bpf program(s) from binary *OBJ* and pin as *PATH*. **bpftool prog
>      load** pins only the first program from the *OBJ* as *PATH*. **bpftool prog
>      loadall** pins all programs from the *OBJ* under *PATH* directory. **type**
> @@ -153,6 +153,11 @@ bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | na
>      program does not support autoattach, bpftool falls back to regular pinning
>      for that program instead.
>  
> +    The **kernel_btf** option allows specifying an external BTF file to replace
> +    the system's own vmlinux BTF file for CO-RE relocations. NOTE that any
> +    other feature (e.g., fentry/fexit programs, struct_ops, etc) will require


Nit: No need for both "e.g." and "etc", they're redundant.


> +    actual kernel BTF like /sys/kernel/btf/vmlinux.
> +


Can we rephrase the second part of the paragraph a little bit please?
“Any other feature” could be clearer, how about:

	Note that any other feature relying on BTF (such as fentry/fexit
	programs, struct_ops) requires the BTF file for the actual
	kernel running on the host, often exposed at
	/sys/kernel/btf/vmlinux.


>      Note: *PATH* must be located in *bpffs* mount. It must not contain a dot
>      character ('.'), which is reserved for future extensions of *bpffs*.
>  
> diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
> index 1ce409a6cbd9..609938c287b7 100644
> --- a/tools/bpf/bpftool/bash-completion/bpftool
> +++ b/tools/bpf/bpftool/bash-completion/bpftool
> @@ -511,7 +511,7 @@ _bpftool()
>                              ;;
>                          *)
>                              COMPREPLY=( $( compgen -W "map" -- "$cur" ) )
> -                            _bpftool_once_attr 'type pinmaps autoattach'
> +                            _bpftool_once_attr 'type pinmaps autoattach kernel_btf'
>                              _bpftool_one_of_list 'offload_dev xdpmeta_dev'
>                              return 0
>                              ;;


Correct, but right before this could you also add the following, please:

	@@ -505,13 +505,13 @@ _bpftool()
	                             _bpftool_get_map_names
	                             return 0
	                             ;;
	-                        pinned|pinmaps)
	+                        pinned|pinmaps|kernel_btf)
	                             _filedir
	                             return 0
	                             ;;
	                         *)

This will make the completion offer file names after the user has typed
"kernel_btf".


> diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> index f010295350be..3b6a361dd0f8 100644
> --- a/tools/bpf/bpftool/prog.c
> +++ b/tools/bpf/bpftool/prog.c
> @@ -1681,8 +1681,17 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
>  		} else if (is_prefix(*argv, "autoattach")) {
>  			auto_attach = true;
>  			NEXT_ARG();
> +		} else if (is_prefix(*argv, "kernel_btf")) {
> +			NEXT_ARG();
> +
> +			if (!REQ_ARGS(1))
> +				goto err_free_reuse_maps;
> +
> +			open_opts.btf_custom_path = GET_ARG();
>  		} else {
> -			p_err("expected no more arguments, 'type', 'map' or 'dev', got: '%s'?",
> +			p_err("expected no more arguments, "
> +			      "'type', 'map', 'dev', 'offload_dev', 'xdpmeta_dev', 'pinmaps', "
> +			      "'autoattach', or 'kernel_btf', got: '%s'?",


Some of them were missing, thanks for this! Can you remove "dev" from
the list, please? It's been deprecated in favour of "offload_dev", to
avoid confusion with "xdpmeta_dev".

pw-bot: cr


>  			      *argv);
>  			goto err_free_reuse_maps;
>  		}
> @@ -2474,6 +2483,7 @@ static int do_help(int argc, char **argv)
>  		"                         [map { idx IDX | name NAME } MAP]\\\n"
>  		"                         [pinmaps MAP_DIR]\n"
>  		"                         [autoattach]\n"
> +		"                         [kernel_btf BTF_DIR]\n"
>  		"       %1$s %2$s attach PROG ATTACH_TYPE [MAP]\n"
>  		"       %1$s %2$s detach PROG ATTACH_TYPE [MAP]\n"
>  		"       %1$s %2$s run PROG \\\n"


Thanks,
Quentin

Re: [PATCH bpf-next v2] bpftool: Add support for custom BTF path in prog load/loadall

[Jiayuan Chen]

May 15, 2025 at 17:17, "Quentin Monnet" <qmo@kernel.org> wrote:

> 
> 2025-05-15 14:50 UTC+0800 ~ Jiayuan Chen <jiayuan.chen@linux.dev>
> 
> > 
> > This patch exposes the btf_custom_path feature to bpftool, allowing users
> > 
> >  to specify a custom BTF file when loading BPF programs using prog load or
> > 
> >  prog loadall commands.
> > 
> >  
> > 
> >  The argument 'btf_custom_path' in libbpf is used for those kernes that
> > 
> 
> Typo: "kernes"
> 
> > 
> > don't have CONFIG_DEBUG_INFO_BTF enabled but still want to perform CO-RE
> > 
> >  relocations.
> > 
> >  
> > 
> >  Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
> > 
> >  ---
> > 
> >  tools/bpf/bpftool/Documentation/bpftool-prog.rst | 7 ++++++-
> > 
> >  tools/bpf/bpftool/bash-completion/bpftool | 2 +-
> > 
> >  tools/bpf/bpftool/prog.c | 12 +++++++++++-
> > 
> >  3 files changed, 18 insertions(+), 3 deletions(-)
> > 
> >  
> > 
> >  diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
> > 
> >  index d6304e01afe0..e60a829ab8d0 100644
> > 
> >  --- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
> > 
> >  +++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
> > 
> >  @@ -127,7 +127,7 @@ bpftool prog pin *PROG* *FILE*
> > 
> >  Note: *FILE* must be located in *bpffs* mount. It must not contain a dot
> > 
> >  character ('.'), which is reserved for future extensions of *bpffs*.
> > 
> >  
> > 
> >  -bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | name *NAME* } *MAP*] [{ offload_dev | xdpmeta_dev } *NAME*] [pinmaps *MAP_DIR*] [autoattach]
> > 
> >  +bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | name *NAME* } *MAP*] [{ offload_dev | xdpmeta_dev } *NAME*] [pinmaps *MAP_DIR*] [autoattach] [kernel_btf *BTF_DIR*]
> > 
> >  Load bpf program(s) from binary *OBJ* and pin as *PATH*. **bpftool prog
> > 
> >  load** pins only the first program from the *OBJ* as *PATH*. **bpftool prog
> > 
> >  loadall** pins all programs from the *OBJ* under *PATH* directory. **type**
> > 
> >  @@ -153,6 +153,11 @@ bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | na
> > 
> >  program does not support autoattach, bpftool falls back to regular pinning
> > 
> >  for that program instead.
> > 
> >  
> > 
> >  + The **kernel_btf** option allows specifying an external BTF file to replace
> > 
> >  + the system's own vmlinux BTF file for CO-RE relocations. NOTE that any
> > 
> >  + other feature (e.g., fentry/fexit programs, struct_ops, etc) will require
> > 
> 
> Nit: No need for both "e.g." and "etc", they're redundant.
> 
> > 
> > + actual kernel BTF like /sys/kernel/btf/vmlinux.
> > 
> >  +
> > 
> 
> Can we rephrase the second part of the paragraph a little bit please?
> 
> “Any other feature” could be clearer, how about:
> 
>  Note that any other feature relying on BTF (such as fentry/fexit
> 
>  programs, struct_ops) requires the BTF file for the actual
> 
>  kernel running on the host, often exposed at
> 
>  /sys/kernel/btf/vmlinux.
> 
> > 
> > Note: *PATH* must be located in *bpffs* mount. It must not contain a dot
> > 
> >  character ('.'), which is reserved for future extensions of *bpffs*.
> > 
> >  
> > 
> >  diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
> > 
> >  index 1ce409a6cbd9..609938c287b7 100644
> > 
> >  --- a/tools/bpf/bpftool/bash-completion/bpftool
> > 
> >  +++ b/tools/bpf/bpftool/bash-completion/bpftool
> > 
> >  @@ -511,7 +511,7 @@ _bpftool()
> > 
> >  ;;
> > 
> >  *)
> > 
> >  COMPREPLY=( $( compgen -W "map" -- "$cur" ) )
> > 
> >  - _bpftool_once_attr 'type pinmaps autoattach'
> > 
> >  + _bpftool_once_attr 'type pinmaps autoattach kernel_btf'
> > 
> >  _bpftool_one_of_list 'offload_dev xdpmeta_dev'
> > 
> >  return 0
> > 
> >  ;;
> > 
> 
> Correct, but right before this could you also add the following, please:
> 
>  @@ -505,13 +505,13 @@ _bpftool()
> 
>  _bpftool_get_map_names
> 
>  return 0
> 
>  ;;
> 
>  - pinned|pinmaps)
> 
>  + pinned|pinmaps|kernel_btf)
> 
>  _filedir
> 
>  return 0
> 
>  ;;
> 
>  *)
> 
> This will make the completion offer file names after the user has typed
> 
> "kernel_btf".
> 
> > 
> > diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> > 
> >  index f010295350be..3b6a361dd0f8 100644
> > 
> >  --- a/tools/bpf/bpftool/prog.c
> > 
> >  +++ b/tools/bpf/bpftool/prog.c
> > 
> >  @@ -1681,8 +1681,17 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
> > 
> >  } else if (is_prefix(*argv, "autoattach")) {
> > 
> >  auto_attach = true;
> > 
> >  NEXT_ARG();
> > 
> >  + } else if (is_prefix(*argv, "kernel_btf")) {
> > 
> >  + NEXT_ARG();
> > 
> >  +
> > 
> >  + if (!REQ_ARGS(1))
> > 
> >  + goto err_free_reuse_maps;
> > 
> >  +
> > 
> >  + open_opts.btf_custom_path = GET_ARG();
> > 
> >  } else {
> > 
> >  - p_err("expected no more arguments, 'type', 'map' or 'dev', got: '%s'?",
> > 
> >  + p_err("expected no more arguments, "
> > 
> >  + "'type', 'map', 'dev', 'offload_dev', 'xdpmeta_dev', 'pinmaps', "
> > 
> >  + "'autoattach', or 'kernel_btf', got: '%s'?",
> > 
> 
> Some of them were missing, thanks for this! Can you remove "dev" from
> 
> the list, please? It's been deprecated in favour of "offload_dev", to
> 
> avoid confusion with "xdpmeta_dev".
> 
> pw-bot: cr
> 
> > 
> > *argv);
> > 
> >  goto err_free_reuse_maps;
> > 
> >  }
> > 
> >  @@ -2474,6 +2483,7 @@ static int do_help(int argc, char **argv)
> > 
> >  " [map { idx IDX | name NAME } MAP]\\\n"
> > 
> >  " [pinmaps MAP_DIR]\n"
> > 
> >  " [autoattach]\n"
> > 
> >  + " [kernel_btf BTF_DIR]\n"
> > 
> >  " %1$s %2$s attach PROG ATTACH_TYPE [MAP]\n"
> > 
> >  " %1$s %2$s detach PROG ATTACH_TYPE [MAP]\n"
> > 
> >  " %1$s %2$s run PROG \\\n"
> > 
> 
> Thanks,
> 
> Quentin
>

Thank you, Quentin. Your suggestions are all very valuable; I will make the updates.

Re: [PATCH bpf-next v2] bpftool: Add support for custom BTF path in prog load/loadall

[Andrii Nakryiko]

On Wed, May 14, 2025 at 11:52 PM Jiayuan Chen <jiayuan.chen@linux.dev> wrote:
>
> This patch exposes the btf_custom_path feature to bpftool, allowing users
> to specify a custom BTF file when loading BPF programs using prog load or
> prog loadall commands.
>
> The argument 'btf_custom_path' in libbpf is used for those kernes that
> don't have CONFIG_DEBUG_INFO_BTF enabled but still want to perform CO-RE
> relocations.
>
> Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
> ---
>  tools/bpf/bpftool/Documentation/bpftool-prog.rst |  7 ++++++-
>  tools/bpf/bpftool/bash-completion/bpftool        |  2 +-
>  tools/bpf/bpftool/prog.c                         | 12 +++++++++++-
>  3 files changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/tools/bpf/bpftool/Documentation/bpftool-prog.rst b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
> index d6304e01afe0..e60a829ab8d0 100644
> --- a/tools/bpf/bpftool/Documentation/bpftool-prog.rst
> +++ b/tools/bpf/bpftool/Documentation/bpftool-prog.rst
> @@ -127,7 +127,7 @@ bpftool prog pin *PROG* *FILE*
>      Note: *FILE* must be located in *bpffs* mount. It must not contain a dot
>      character ('.'), which is reserved for future extensions of *bpffs*.
>
> -bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | name *NAME* } *MAP*] [{ offload_dev | xdpmeta_dev } *NAME*] [pinmaps *MAP_DIR*] [autoattach]
> +bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | name *NAME* } *MAP*] [{ offload_dev | xdpmeta_dev } *NAME*] [pinmaps *MAP_DIR*] [autoattach] [kernel_btf *BTF_DIR*]
>      Load bpf program(s) from binary *OBJ* and pin as *PATH*. **bpftool prog
>      load** pins only the first program from the *OBJ* as *PATH*. **bpftool prog
>      loadall** pins all programs from the *OBJ* under *PATH* directory. **type**
> @@ -153,6 +153,11 @@ bpftool prog { load | loadall } *OBJ* *PATH* [type *TYPE*] [map { idx *IDX* | na
>      program does not support autoattach, bpftool falls back to regular pinning
>      for that program instead.
>
> +    The **kernel_btf** option allows specifying an external BTF file to replace
> +    the system's own vmlinux BTF file for CO-RE relocations. NOTE that any
> +    other feature (e.g., fentry/fexit programs, struct_ops, etc) will require
> +    actual kernel BTF like /sys/kernel/btf/vmlinux.
> +
>      Note: *PATH* must be located in *bpffs* mount. It must not contain a dot
>      character ('.'), which is reserved for future extensions of *bpffs*.
>
> diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool
> index 1ce409a6cbd9..609938c287b7 100644
> --- a/tools/bpf/bpftool/bash-completion/bpftool
> +++ b/tools/bpf/bpftool/bash-completion/bpftool
> @@ -511,7 +511,7 @@ _bpftool()
>                              ;;
>                          *)
>                              COMPREPLY=( $( compgen -W "map" -- "$cur" ) )
> -                            _bpftool_once_attr 'type pinmaps autoattach'
> +                            _bpftool_once_attr 'type pinmaps autoattach kernel_btf'
>                              _bpftool_one_of_list 'offload_dev xdpmeta_dev'
>                              return 0
>                              ;;
> diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
> index f010295350be..3b6a361dd0f8 100644
> --- a/tools/bpf/bpftool/prog.c
> +++ b/tools/bpf/bpftool/prog.c
> @@ -1681,8 +1681,17 @@ static int load_with_options(int argc, char **argv, bool first_prog_only)
>                 } else if (is_prefix(*argv, "autoattach")) {
>                         auto_attach = true;
>                         NEXT_ARG();
> +               } else if (is_prefix(*argv, "kernel_btf")) {
> +                       NEXT_ARG();
> +
> +                       if (!REQ_ARGS(1))
> +                               goto err_free_reuse_maps;
> +
> +                       open_opts.btf_custom_path = GET_ARG();
>                 } else {
> -                       p_err("expected no more arguments, 'type', 'map' or 'dev', got: '%s'?",
> +                       p_err("expected no more arguments, "
> +                             "'type', 'map', 'dev', 'offload_dev', 'xdpmeta_dev', 'pinmaps', "
> +                             "'autoattach', or 'kernel_btf', got: '%s'?",
>                               *argv);
>                         goto err_free_reuse_maps;
>                 }
> @@ -2474,6 +2483,7 @@ static int do_help(int argc, char **argv)
>                 "                         [map { idx IDX | name NAME } MAP]\\\n"
>                 "                         [pinmaps MAP_DIR]\n"
>                 "                         [autoattach]\n"
> +               "                         [kernel_btf BTF_DIR]\n"

Is it a DIR or a FILE/PATH?

>                 "       %1$s %2$s attach PROG ATTACH_TYPE [MAP]\n"
>                 "       %1$s %2$s detach PROG ATTACH_TYPE [MAP]\n"
>                 "       %1$s %2$s run PROG \\\n"
> --
> 2.47.1
>
>