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Date: Fri, 9 Jun 2017 12:38:50 +0100
From: Will Deacon <will.deacon@arm.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@redhat.com>,
        Jessica Yu <jeyu@kernel.org>, Rusty Russell <rusty@rustcorp.com.au>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] arm64: ftrace: fix building without CONFIG_MODULES
Message-ID: <20170609113850.GF13955@arm.com>
References: <20170609102807.2992510-1-arnd@arndb.de>
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Hi Arnd,

On Fri, Jun 09, 2017 at 12:27:06PM +0200, Arnd Bergmann wrote:
> When CONFIG_MODULES is disabled, we cannot dereference a module pointer:
> 
> arch/arm64/kernel/ftrace.c: In function 'ftrace_make_call':
> arch/arm64/kernel/ftrace.c:107:36: error: dereferencing pointer to incomplete type 'struct module'
>    trampoline = (unsigned long *)mod->arch.ftrace_trampoline;
> 
> Also, the within_module() function is not defined:
> 
> arch/arm64/kernel/ftrace.c: In function 'ftrace_make_nop':
> arch/arm64/kernel/ftrace.c:171:8: error: implicit declaration of function 'within_module'; did you mean 'init_module'? [-Werror=implicit-function-declaration]
> 
> This addresses both by adding the appropriate stubs.
> 
> Fixes: e71a4e1bebaf ("arm64: ftrace: add support for far branches to dynamic ftrace")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  arch/arm64/include/asm/module.h | 6 ++++++
>  arch/arm64/kernel/ftrace.c      | 2 +-
>  include/linux/module.h          | 5 +++++
>  3 files changed, 12 insertions(+), 1 deletion(-)

I can't seem to reproduce this simply by disabling MODULES in defconfig.
Could you share your .config, please?

Will