Re: [RFC PATCH 15/15] drivers/acrn: add the support of offline SOS cpu

[Zhao, Yakui]

On 2019å08æ19æ 18:34, Dan Carpenter wrote:
> On Fri, Aug 16, 2019 at 10:25:56AM +0800, Zhao Yakui wrote:
> > diff --git a/drivers/staging/acrn/acrn_dev.c b/drivers/staging/acrn/acrn_dev.c
> > index 0602125..6868003 100644
> > --- a/drivers/staging/acrn/acrn_dev.c
> > +++ b/drivers/staging/acrn/acrn_dev.c
> > @@ -588,6 +588,41 @@ static const struct file_operations fops = {
> >   #define SUPPORT_HV_API_VERSION_MAJOR	1
> >   #define SUPPORT_HV_API_VERSION_MINOR	0
> >   
> > +static ssize_t
> > +offline_cpu_store(struct device *dev,
> > +			struct device_attribute *attr,
> > +			const char *buf, size_t count)
> > +{
> > +#ifdef CONFIG_X86
> > +	u64 cpu, lapicid;
> > +
> > +	if (kstrtoull(buf, 0, &cpu) < 0)
> > +		return -EINVAL;

Thanks for the review.

Make sense.
The error code will be preserved.

> Preserve the error code.
>
> 	ret = kstrtoull(buf, 0, &cpu);
> 	if (ret)
> 		return ret;


> > +
> > +	if (cpu_possible(cpu)) {
>
> You can't pass unchecked cpu values to cpu_possible() or it results in
> an out of bounds read if cpu is >= than nr_cpu_ids.

OK. It will add the check of "cpu < num_possibles_cpu()" to avoid the 
out of bounds.

> regards,
> dan carpenter