On Fri, Apr 25, 2014 at 07:40:04PM +0200, Mathieu Souchaud wrote:
> Check return code of every function called.
>
> Signed-off-by: Mathieu Souchaud <mattieu.souchaud@xxxxxxx>
> ---
> 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;
Actually, this should partially unwind what has been created already,
like this:
if (err)
goto err_device_create;
and then at that label, you can do:
err_device_create:
while (--i > 0)
mce_device_remove(i);
cpu_notifier_register_done();
And then here come your other labels:
err_out_mem:
....
And so on. Makes sense?
> 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;
This needs to be a label which goes before err_device_create above and
which does
err_reg_hotcpu:
unregister_syscore_ops(&mce_syscore_ops);
>
> /* register character device /dev/mcelog */
> - misc_register(&mce_chrdev_device);
> + err = misc_register(&mce_chrdev_device);
> + if (err)
> + goto err_out_mem;
And this has to go to the top-label which unwinds all the work, along
with the mce percpu devices like:
for_each_online_cpu(i)
mce_device_remove(i);
unregister_hotcpu_notifier(&mce_cpu_notifier);
...
and so on.
Ok, am I making sense?
Don't be afraid to give it a try, even if it is wrong - we'll get it
right eventually :-)
For testing, you can use a kvm guest and "inject" errors in the
registration code just to see whether it works as expected.
And feel free to ask questions if something's not clear.
Thanks!
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
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