LinuxLists.cc - [PATCH] arm64: ftrace: Define ftrace_stub_graph only with FUNCTION_GRAPH

2022-11-09 20:02:44

Subject: [PATCH] arm64: ftrace: Define ftrace_stub_graph only with FUNCTION_GRAPH_TRACER

The 0-day bot reports that arm64 builds with CONFIG_CFI_CLANG +
CONFIG_FTRACE are broken when CONFIG_FUNCTION_GRAPH_TRACER is not
enabled:

ld.lld: error: undefined symbol: __kcfi_typeid_ftrace_stub_graph
>>> referenced by entry-ftrace.S:299 (arch/arm64/kernel/entry-ftrace.S:299)
>>> arch/arm64/kernel/entry-ftrace.o:(.text+0x48) in archive vmlinux.a

This is caused by ftrace_stub_graph using SYM_TYPE_FUNC_START when
the address of the function is not taken in any C translation unit.

Fix the build by only defining ftrace_stub_graph when it's actually
needed, i.e. with CONFIG_FUNCTION_GRAPH_TRACER.

Link: https://lore.kernel.org/lkml/[email protected]/
Fixes: 883bbbffa5a4 ("ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph()")
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Sami Tolvanen <[email protected]>
---
arch/arm64/kernel/entry-ftrace.S | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
index 795344ab4ec4..322a831f8ede 100644
--- a/arch/arm64/kernel/entry-ftrace.S
+++ b/arch/arm64/kernel/entry-ftrace.S
@@ -299,11 +299,11 @@ SYM_TYPED_FUNC_START(ftrace_stub)
ret
SYM_FUNC_END(ftrace_stub)

+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
SYM_TYPED_FUNC_START(ftrace_stub_graph)
ret
SYM_FUNC_END(ftrace_stub_graph)

-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
/*
* void return_to_handler(void)
*

base-commit: f141df371335645ce29a87d9683a3f79fba7fd67
--
2.38.1.431.g37b22c650d-goog

2022-11-11 13:45:51

by Masami Hiramatsu

[permalink] [raw]

Subject: Re: [PATCH] arm64: ftrace: Define ftrace_stub_graph only with FUNCTION_GRAPH_TRACER

On Wed, 9 Nov 2022 19:28:31 +0000
Sami Tolvanen <[email protected]> wrote:

> The 0-day bot reports that arm64 builds with CONFIG_CFI_CLANG +
> CONFIG_FTRACE are broken when CONFIG_FUNCTION_GRAPH_TRACER is not
> enabled:
>
> ld.lld: error: undefined symbol: __kcfi_typeid_ftrace_stub_graph
> >>> referenced by entry-ftrace.S:299 (arch/arm64/kernel/entry-ftrace.S:299)
> >>> arch/arm64/kernel/entry-ftrace.o:(.text+0x48) in archive vmlinux.a
>
> This is caused by ftrace_stub_graph using SYM_TYPE_FUNC_START when
> the address of the function is not taken in any C translation unit.
>
> Fix the build by only defining ftrace_stub_graph when it's actually
> needed, i.e. with CONFIG_FUNCTION_GRAPH_TRACER.
>
> Link: https://lore.kernel.org/lkml/[email protected]/
> Fixes: 883bbbffa5a4 ("ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph()")
> Reported-by: kernel test robot <[email protected]>
> Signed-off-by: Sami Tolvanen <[email protected]>

This looks good to me.

Reviewed-by: Masami Hiramatsu (Google) <[email protected]>

Thanks!

> ---
> arch/arm64/kernel/entry-ftrace.S | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
> index 795344ab4ec4..322a831f8ede 100644
> --- a/arch/arm64/kernel/entry-ftrace.S
> +++ b/arch/arm64/kernel/entry-ftrace.S
> @@ -299,11 +299,11 @@ SYM_TYPED_FUNC_START(ftrace_stub)
> ret
> SYM_FUNC_END(ftrace_stub)
>
> +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> SYM_TYPED_FUNC_START(ftrace_stub_graph)
> ret
> SYM_FUNC_END(ftrace_stub_graph)
>
> -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> /*
> * void return_to_handler(void)
> *
>
> base-commit: f141df371335645ce29a87d9683a3f79fba7fd67
> --
> 2.38.1.431.g37b22c650d-goog
>

--
Masami Hiramatsu (Google) <[email protected]>

2022-11-11 17:26:26

by Mark Rutland

[permalink] [raw]

Subject: Re: [PATCH] arm64: ftrace: Define ftrace_stub_graph only with FUNCTION_GRAPH_TRACER

On Wed, Nov 09, 2022 at 07:28:31PM +0000, Sami Tolvanen wrote:
> The 0-day bot reports that arm64 builds with CONFIG_CFI_CLANG +
> CONFIG_FTRACE are broken when CONFIG_FUNCTION_GRAPH_TRACER is not
> enabled:
>
> ld.lld: error: undefined symbol: __kcfi_typeid_ftrace_stub_graph
> >>> referenced by entry-ftrace.S:299 (arch/arm64/kernel/entry-ftrace.S:299)
> >>> arch/arm64/kernel/entry-ftrace.o:(.text+0x48) in archive vmlinux.a
>
> This is caused by ftrace_stub_graph using SYM_TYPE_FUNC_START when
> the address of the function is not taken in any C translation unit.
>
> Fix the build by only defining ftrace_stub_graph when it's actually
> needed, i.e. with CONFIG_FUNCTION_GRAPH_TRACER.
>
> Link: https://lore.kernel.org/lkml/[email protected]/
> Fixes: 883bbbffa5a4 ("ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph()")
> Reported-by: kernel test robot <[email protected]>
> Signed-off-by: Sami Tolvanen <[email protected]>

Acked-by: Mark Rutland <[email protected]>

Mark.

> ---
> arch/arm64/kernel/entry-ftrace.S | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S
> index 795344ab4ec4..322a831f8ede 100644
> --- a/arch/arm64/kernel/entry-ftrace.S
> +++ b/arch/arm64/kernel/entry-ftrace.S
> @@ -299,11 +299,11 @@ SYM_TYPED_FUNC_START(ftrace_stub)
> ret
> SYM_FUNC_END(ftrace_stub)
>
> +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> SYM_TYPED_FUNC_START(ftrace_stub_graph)
> ret
> SYM_FUNC_END(ftrace_stub_graph)
>
> -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> /*
> * void return_to_handler(void)
> *
>
> base-commit: f141df371335645ce29a87d9683a3f79fba7fd67
> --
> 2.38.1.431.g37b22c650d-goog
>

2022-11-11 19:44:40

by Kees Cook

[permalink] [raw]

Subject: Re: [PATCH] arm64: ftrace: Define ftrace_stub_graph only with FUNCTION_GRAPH_TRACER

2022-11-14 14:00:10

by Catalin Marinas

[permalink] [raw]

Subject: Re: [PATCH] arm64: ftrace: Define ftrace_stub_graph only with FUNCTION_GRAPH_TRACER

On Wed, 9 Nov 2022 19:28:31 +0000, Sami Tolvanen wrote:
> The 0-day bot reports that arm64 builds with CONFIG_CFI_CLANG +
> CONFIG_FTRACE are broken when CONFIG_FUNCTION_GRAPH_TRACER is not
> enabled:
>
> ld.lld: error: undefined symbol: __kcfi_typeid_ftrace_stub_graph
> >>> referenced by entry-ftrace.S:299 (arch/arm64/kernel/entry-ftrace.S:299)
> >>> arch/arm64/kernel/entry-ftrace.o:(.text+0x48) in archive vmlinux.a
>
> [...]

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm64: ftrace: Define ftrace_stub_graph only with FUNCTION_GRAPH_TRACER
https://git.kernel.org/arm64/c/2598ac6ec493

--
Catalin