From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
To: Sami Tolvanen <samitolvanen@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Kees Cook <keescook@chromium.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: ftrace: Define ftrace_stub_graph only with FUNCTION_GRAPH_TRACER
Date: Fri, 11 Nov 2022 22:29:00 +0900 [thread overview]
Message-ID: <20221111222900.0e4a1d4768730b9784249c86@kernel.org> (raw)
In-Reply-To: <20221109192831.3057131-1-samitolvanen@google.com>
On Wed, 9 Nov 2022 19:28:31 +0000
Sami Tolvanen <samitolvanen@google.com> 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/202210251659.tRMs78RH-lkp@intel.com/
> Fixes: 883bbbffa5a4 ("ftrace,kcfi: Separate ftrace_stub() and ftrace_stub_graph()")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
This looks good to me.
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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) <mhiramat@kernel.org>
next prev parent reply other threads:[~2022-11-11 13:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-09 19:28 Sami Tolvanen
2022-11-11 13:29 ` Masami Hiramatsu [this message]
2022-11-11 16:09 ` Mark Rutland
2022-11-11 18:32 ` Kees Cook
2022-11-14 13:28 ` Catalin Marinas
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