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* [PATCH bpf-next] bpf: Increase size of BTF_ID_LIST without CONFIG_DEBUG_INFO_BTF again
@ 2023-03-07 15:14 Nathan Chancellor
  2023-03-07 15:26 ` Tom Rix
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Nathan Chancellor @ 2023-03-07 15:14 UTC (permalink / raw)
  To: ast, daniel, andrii
  Cc: martin.lau, song, yhs, john.fastabend, kpsingh, sdf, haoluo,
	jolsa, ndesaulniers, trix, bpf, linux-kernel, llvm, patches,
	Nathan Chancellor

After commit 66e3a13e7c2c ("bpf: Add bpf_dynptr_slice and
bpf_dynptr_slice_rdwr"), clang builds without CONFIG_DEBUG_INFO_BTF
warn:

  kernel/bpf/verifier.c:10298:24: warning: array index 16 is past the end of the array (that has type 'u32[16]' (aka 'unsigned int[16]')) [-Warray-bounds]
                                     meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) {
                                                     ^                  ~~~~~~~~~~~~~~~~~~~~~~~~
  kernel/bpf/verifier.c:9150:1: note: array 'special_kfunc_list' declared here
  BTF_ID_LIST(special_kfunc_list)
  ^
  include/linux/btf_ids.h:207:27: note: expanded from macro 'BTF_ID_LIST'
  #define BTF_ID_LIST(name) static u32 __maybe_unused name[16];
                            ^
  1 warning generated.

A warning of this nature was previously addressed by
commit beb3d47d1d3d ("bpf: Fix a BTF_ID_LIST bug with
CONFIG_DEBUG_INFO_BTF not set") but there have been new kfuncs added
since then.

Quadruple the size of the CONFIG_DEBUG_INFO_BTF=n definition so that
this problem is unlikely to show up for some time.

Link: https://github.com/ClangBuiltLinux/linux/issues/1810
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
 include/linux/btf_ids.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index 3a4f7cd882ca..00950cc03bff 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -204,7 +204,7 @@ extern struct btf_id_set8 name;
 
 #else
 
-#define BTF_ID_LIST(name) static u32 __maybe_unused name[16];
+#define BTF_ID_LIST(name) static u32 __maybe_unused name[64];
 #define BTF_ID(prefix, name)
 #define BTF_ID_FLAGS(prefix, name, ...)
 #define BTF_ID_UNUSED

---
base-commit: 36e5e391a25af28dc1f4586f95d577b38ff4ed72
change-id: 20230307-bpf-kfuncs-warray-bounds-c2040e8ee7ee

Best regards,
-- 
Nathan Chancellor <nathan@kernel.org>


^ permalink raw reply related	[flat|nested] 4+ messages in thread

* Re: [PATCH bpf-next] bpf: Increase size of BTF_ID_LIST without CONFIG_DEBUG_INFO_BTF again
  2023-03-07 15:14 [PATCH bpf-next] bpf: Increase size of BTF_ID_LIST without CONFIG_DEBUG_INFO_BTF again Nathan Chancellor
@ 2023-03-07 15:26 ` Tom Rix
  2023-03-07 15:53 ` Alexei Starovoitov
  2023-03-07 16:00 ` patchwork-bot+netdevbpf
  2 siblings, 0 replies; 4+ messages in thread
From: Tom Rix @ 2023-03-07 15:26 UTC (permalink / raw)
  To: Nathan Chancellor, ast, daniel, andrii
  Cc: martin.lau, song, yhs, john.fastabend, kpsingh, sdf, haoluo,
	jolsa, ndesaulniers, bpf, linux-kernel, llvm, patches


On 3/7/23 7:14 AM, Nathan Chancellor wrote:
> After commit 66e3a13e7c2c ("bpf: Add bpf_dynptr_slice and
> bpf_dynptr_slice_rdwr"), clang builds without CONFIG_DEBUG_INFO_BTF
> warn:
>
>    kernel/bpf/verifier.c:10298:24: warning: array index 16 is past the end of the array (that has type 'u32[16]' (aka 'unsigned int[16]')) [-Warray-bounds]
>                                       meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) {
>                                                       ^                  ~~~~~~~~~~~~~~~~~~~~~~~~
>    kernel/bpf/verifier.c:9150:1: note: array 'special_kfunc_list' declared here
>    BTF_ID_LIST(special_kfunc_list)
>    ^
>    include/linux/btf_ids.h:207:27: note: expanded from macro 'BTF_ID_LIST'
>    #define BTF_ID_LIST(name) static u32 __maybe_unused name[16];
>                              ^
>    1 warning generated.
>
> A warning of this nature was previously addressed by
> commit beb3d47d1d3d ("bpf: Fix a BTF_ID_LIST bug with
> CONFIG_DEBUG_INFO_BTF not set") but there have been new kfuncs added
> since then.
>
> Quadruple the size of the CONFIG_DEBUG_INFO_BTF=n definition so that
> this problem is unlikely to show up for some time.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1810
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>

This has a better commit message, let's use this one.

FWIW, gcc 13 -Warray-bounds, did not catch this.

Reviewed-by: Tom Rix <trix@redhat.com>

> ---
>   include/linux/btf_ids.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
> index 3a4f7cd882ca..00950cc03bff 100644
> --- a/include/linux/btf_ids.h
> +++ b/include/linux/btf_ids.h
> @@ -204,7 +204,7 @@ extern struct btf_id_set8 name;
>   
>   #else
>   
> -#define BTF_ID_LIST(name) static u32 __maybe_unused name[16];
> +#define BTF_ID_LIST(name) static u32 __maybe_unused name[64];
>   #define BTF_ID(prefix, name)
>   #define BTF_ID_FLAGS(prefix, name, ...)
>   #define BTF_ID_UNUSED
>
> ---
> base-commit: 36e5e391a25af28dc1f4586f95d577b38ff4ed72
> change-id: 20230307-bpf-kfuncs-warray-bounds-c2040e8ee7ee
>
> Best regards,


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH bpf-next] bpf: Increase size of BTF_ID_LIST without CONFIG_DEBUG_INFO_BTF again
  2023-03-07 15:14 [PATCH bpf-next] bpf: Increase size of BTF_ID_LIST without CONFIG_DEBUG_INFO_BTF again Nathan Chancellor
  2023-03-07 15:26 ` Tom Rix
@ 2023-03-07 15:53 ` Alexei Starovoitov
  2023-03-07 16:00 ` patchwork-bot+netdevbpf
  2 siblings, 0 replies; 4+ messages in thread
From: Alexei Starovoitov @ 2023-03-07 15:53 UTC (permalink / raw)
  To: Nathan Chancellor
  Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
	Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
	KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
	Nick Desaulniers, Tom Rix, bpf, LKML, clang-built-linux, patches

On Tue, Mar 7, 2023 at 7:14 AM Nathan Chancellor <nathan@kernel.org> wrote:
>
> After commit 66e3a13e7c2c ("bpf: Add bpf_dynptr_slice and
> bpf_dynptr_slice_rdwr"), clang builds without CONFIG_DEBUG_INFO_BTF

please don't break commit subj into multiple lines.
I've fixed it manually this time while applying.

> warn:
>
>   kernel/bpf/verifier.c:10298:24: warning: array index 16 is past the end of the array (that has type 'u32[16]' (aka 'unsigned int[16]')) [-Warray-bounds]
>                                      meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) {
>                                                      ^                  ~~~~~~~~~~~~~~~~~~~~~~~~
>   kernel/bpf/verifier.c:9150:1: note: array 'special_kfunc_list' declared here
>   BTF_ID_LIST(special_kfunc_list)
>   ^
>   include/linux/btf_ids.h:207:27: note: expanded from macro 'BTF_ID_LIST'
>   #define BTF_ID_LIST(name) static u32 __maybe_unused name[16];
>                             ^
>   1 warning generated.
>
> A warning of this nature was previously addressed by
> commit beb3d47d1d3d ("bpf: Fix a BTF_ID_LIST bug with
> CONFIG_DEBUG_INFO_BTF not set") but there have been new kfuncs added

and here.

> since then.
>
> Quadruple the size of the CONFIG_DEBUG_INFO_BTF=n definition so that
> this problem is unlikely to show up for some time.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1810
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
>  include/linux/btf_ids.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
> index 3a4f7cd882ca..00950cc03bff 100644
> --- a/include/linux/btf_ids.h
> +++ b/include/linux/btf_ids.h
> @@ -204,7 +204,7 @@ extern struct btf_id_set8 name;
>
>  #else
>
> -#define BTF_ID_LIST(name) static u32 __maybe_unused name[16];
> +#define BTF_ID_LIST(name) static u32 __maybe_unused name[64];
>  #define BTF_ID(prefix, name)
>  #define BTF_ID_FLAGS(prefix, name, ...)
>  #define BTF_ID_UNUSED
>
> ---
> base-commit: 36e5e391a25af28dc1f4586f95d577b38ff4ed72
> change-id: 20230307-bpf-kfuncs-warray-bounds-c2040e8ee7ee
>
> Best regards,
> --
> Nathan Chancellor <nathan@kernel.org>
>

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH bpf-next] bpf: Increase size of BTF_ID_LIST without CONFIG_DEBUG_INFO_BTF again
  2023-03-07 15:14 [PATCH bpf-next] bpf: Increase size of BTF_ID_LIST without CONFIG_DEBUG_INFO_BTF again Nathan Chancellor
  2023-03-07 15:26 ` Tom Rix
  2023-03-07 15:53 ` Alexei Starovoitov
@ 2023-03-07 16:00 ` patchwork-bot+netdevbpf
  2 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2023-03-07 16:00 UTC (permalink / raw)
  To: Nathan Chancellor
  Cc: ast, daniel, andrii, martin.lau, song, yhs, john.fastabend,
	kpsingh, sdf, haoluo, jolsa, ndesaulniers, trix, bpf,
	linux-kernel, llvm, patches

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Tue, 07 Mar 2023 08:14:06 -0700 you wrote:
> After commit 66e3a13e7c2c ("bpf: Add bpf_dynptr_slice and
> bpf_dynptr_slice_rdwr"), clang builds without CONFIG_DEBUG_INFO_BTF
> warn:
> 
>   kernel/bpf/verifier.c:10298:24: warning: array index 16 is past the end of the array (that has type 'u32[16]' (aka 'unsigned int[16]')) [-Warray-bounds]
>                                      meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) {
>                                                      ^                  ~~~~~~~~~~~~~~~~~~~~~~~~
>   kernel/bpf/verifier.c:9150:1: note: array 'special_kfunc_list' declared here
>   BTF_ID_LIST(special_kfunc_list)
>   ^
>   include/linux/btf_ids.h:207:27: note: expanded from macro 'BTF_ID_LIST'
>   #define BTF_ID_LIST(name) static u32 __maybe_unused name[16];
>                             ^
>   1 warning generated.
> 
> [...]

Here is the summary with links:
  - [bpf-next] bpf: Increase size of BTF_ID_LIST without CONFIG_DEBUG_INFO_BTF again
    https://git.kernel.org/bpf/bpf-next/c/2d5bcdcda879

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html



^ permalink raw reply	[flat|nested] 4+ messages in thread

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2023-03-07 15:14 [PATCH bpf-next] bpf: Increase size of BTF_ID_LIST without CONFIG_DEBUG_INFO_BTF again Nathan Chancellor
2023-03-07 15:26 ` Tom Rix
2023-03-07 15:53 ` Alexei Starovoitov
2023-03-07 16:00 ` patchwork-bot+netdevbpf

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