From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Date: Mon, 24 Jan 2022 09:20:07 +0000
Subject: Re: [PATCH -next] exit: export make_task_dead()
Message-Id: <Ye5vR609miJCKdYa@infradead.org>
List-Id: <linux-ia64.vger.kernel.org>
References: <20220122174834.6493-1-rdunlap@infradead.org>
In-Reply-To: <20220122174834.6493-1-rdunlap@infradead.org>
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To: Randy Dunlap <rdunlap@infradead.org>
Cc: linux-kernel@vger.kernel.org, "Eric W. Biederman" <ebiederm@xmission.com>, linux-ia64@vger.kernel.org, Tony Luck <tony.luck@intel.com>, kernel test robot <lkp@intel.com>

On Sat, Jan 22, 2022 at 09:48:34AM -0800, Randy Dunlap wrote:
> In a config file from "kernel test robot <lkp@intel.com>" for a
> different problem, this linker error was exposed when
> CONFIG_IA64_MCA_RECOVERY=m.
> 
> We could either export make_task_dead() or restrict IA64_MCA_RECOVERY
> to a bool Kconfig symbol instead of a tristate symbol, so go with the
> EXPORT_SYMBOL() path.
> 
> Fixes this build error:
> 
> ERROR: modpost: "make_task_dead" [arch/ia64/kernel/mca_recovery.ko] undefined!
> 
> Fixes: 0e25498f8cd4 ("exit: Add and use make_task_dead.")
> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
> Cc: linux-ia64@vger.kernel.org
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: kernel test robot <lkp@intel.com>
> ---
>  kernel/exit.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> --- linux-next-20220121.orig/kernel/exit.c
> +++ linux-next-20220121/kernel/exit.c
> @@ -896,6 +896,7 @@ void __noreturn make_task_dead(int signr
>  
>  	do_exit(signr);
>  }
> +EXPORT_SYMBOL(make_task_dead);

EXPORT_SYMBOL_GPL and restricted, please.

Or even better: force the mca recovery code to be built in.