linux-kernel - Re: [PATCH] x86/mce: Don't unregister CPU hotplug notifier in error path

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Date:	Fri, 20 Jun 2014 22:04:37 -0400
From:	Boris Ostrovsky <boris.ostrovsky@...cle.com>
To:	Borislav Petkov <bp@...en8.de>
CC:	tony.luck@...el.com, linux-kernel@...r.kernel.org,
	linux-edac@...r.kernel.org, mattieu.souchaud@...e.fr
Subject: Re: [PATCH] x86/mce: Don't unregister CPU hotplug notifier in error
 path

On 06/20/2014 05:11 PM, Borislav Petkov wrote:
> On Fri, Jun 20, 2014 at 04:43:37PM -0400, Boris Ostrovsky wrote:
>> We are getting CPU_ONLINE notifier for ASPs during boot:
> Bah, that's craptastic. Hmm, ok, let's try this instead:

I'll try it later but this doesn't look sufficient to me: we might not 
reach this point if subsys_system_register() or zalloc_cpumask_var() 
fail.  We could register the notifier as the first thing in this routine 
(probably after mce_available() succeeds).


-boris

>
> --
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> index bb92f38153b2..9a79c8dbd8e8 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -2451,6 +2451,12 @@ static __init int mcheck_init_device(void)
>   	for_each_online_cpu(i) {
>   		err = mce_device_create(i);
>   		if (err) {
> +			/*
> +			 * Register notifier anyway (and do not unreg it) so
> +			 * that we don't leave undeleted timers, see notifier
> +			 * callback above.
> +			 */
> +			__register_hotcpu_notifier(&mce_cpu_notifier);
>   			cpu_notifier_register_done();
>   			goto err_device_create;
>   		}
> @@ -2471,10 +2477,6 @@ static __init int mcheck_init_device(void)
>   err_register:
>   	unregister_syscore_ops(&mce_syscore_ops);
>   
> -	cpu_notifier_register_begin();
> -	__unregister_hotcpu_notifier(&mce_cpu_notifier);
> -	cpu_notifier_register_done();
> -
>   err_device_create:
>   	/*
>   	 * We didn't keep track of which devices were created above, but
>

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