linux-kernel - Re: [PATCH] x86/mce: Improve mcheck_init

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Date:	Fri, 25 Apr 2014 19:47:12 +0200
From:	mathieu souchaud <mattieu.souchaud@...e.fr>
To:	tony.luck@...el.com, bp@...en8.de, tglx@...utronix.de,
	mingo@...hat.com, hpa@...or.com, x86@...nel.org,
	linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel-janitors@...r.kernel.org
Subject: Re: [PATCH] x86/mce: Improve mcheck_init_device() error handling.

In this patch, unwindind is still not perfect from the 
mce_device_create() calls. I guess, from this point, on error we should 
call mce_device_remove on every created device. But I think this will 
make the code rather complex. And I am not too confident on this kind of 
modification as I don't know much about MCE.

Mathieu S.

Le 25/04/2014 19:40, Mathieu Souchaud a écrit :
> Check return code of every function called.
>
> Signed-off-by: Mathieu Souchaud <mattieu.souchaud@...e.fr>
> ---
>   arch/x86/kernel/cpu/mcheck/mce.c |   30 +++++++++++++++++++++++-------
>   1 file changed, 23 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> index 68317c8..b865285 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -2437,33 +2437,49 @@ static __init int mcheck_init_device(void)
>   	int err;
>   	int i = 0;
>   
> -	if (!mce_available(&boot_cpu_data))
> -		return -EIO;
> +	if (!mce_available(&boot_cpu_data)) {
> +		err = -EIO;
> +		goto err_out;
> +	}
>   
> -	zalloc_cpumask_var(&mce_device_initialized, GFP_KERNEL);
> +	if (!zalloc_cpumask_var(&mce_device_initialized, GFP_KERNEL)) {
> +		err = -ENOMEM;
> +		goto err_out;
> +	}
>   
>   	mce_init_banks();
>   
>   	err = subsys_system_register(&mce_subsys, NULL);
>   	if (err)
> -		return err;
> +		goto err_out_mem;
>   
>   	cpu_notifier_register_begin();
>   	for_each_online_cpu(i) {
>   		err = mce_device_create(i);
>   		if (err) {
>   			cpu_notifier_register_done();
> -			return err;
> +			goto err_out_mem;
>   		}
>   	}
>   
>   	register_syscore_ops(&mce_syscore_ops);
> -	__register_hotcpu_notifier(&mce_cpu_notifier);
> +	err = __register_hotcpu_notifier(&mce_cpu_notifier);
>   	cpu_notifier_register_done();
> +	if (err)
> +		goto err_out_mem;
>   
>   	/* register character device /dev/mcelog */
> -	misc_register(&mce_chrdev_device);
> +	err = misc_register(&mce_chrdev_device);
> +	if (err)
> +		goto err_out_mem;
> +
> +	return 0;
> +
> +err_out_mem:
> +	free_cpumask_var(mce_device_initialized);
>   
> +err_out:
> +	pr_err("Unable to init device /dev/mcelog (rc: %d)\n", err);
>   	return err;
>   }
>   device_initcall_sync(mcheck_init_device);

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