Re: [PATCH v2] x86/mce: Improve mcheck_init_device() error handling

[mathieu souchaud <rodolphe.souchaud@free.fr>]

I took some time to make a light kvm guest and "inject" errors. It seems to work fine (after solving a deadlock issue :) ).

Mathieu S.

Le 03/05/2014 23:03, Mathieu Souchaud a écrit :
> Check return code of every function called by mcheck_init_device().
>
> Signed-off-by: Mathieu Souchaud <mattieu.souchaud@free.fr>
> ---
>   arch/x86/kernel/cpu/mcheck/mce.c |   49 +++++++++++++++++++++++++++++++-------
>   1 file changed, 41 insertions(+), 8 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> index 68317c8..284cfad 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -2437,32 +2437,65 @@ 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_device_create;
>   		}
>   	}
>   
>   	register_syscore_ops(&mce_syscore_ops);
> -	__register_hotcpu_notifier(&mce_cpu_notifier);
> +	err = __register_hotcpu_notifier(&mce_cpu_notifier);
> +	if (err)
> +		goto err_reg_hotcpu;
>   	cpu_notifier_register_done();
>   
>   	/* register character device /dev/mcelog */
> -	misc_register(&mce_chrdev_device);
> +	err = misc_register(&mce_chrdev_device);
> +	if (err)
> +		goto err_register;
> +
> +	return 0;
> +
> +
> +err_register:
> +	cpu_notifier_register_begin();
> +	__unregister_hotcpu_notifier(&mce_cpu_notifier);
> +
> +err_reg_hotcpu:
> +	unregister_syscore_ops(&mce_syscore_ops);
> +
> +err_device_create:
> +	/*
> +	 * mce_device_remove behave properly if mce_device_create was not
> +	 * called on that device.
> +	 */
> +	for_each_possible_cpu(i)
> +		mce_device_remove(i);
> +	cpu_notifier_register_done();
> +
> +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;
>   }