Re: [Xen-devel] [PATCH 09/19] xen: lock target domain in do_domctl common code

[Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>]

On 11/19/2012 04:24 AM, Jan Beulich wrote:
>>>> On 16.11.12 at 19:28, Daniel De Graaf <dgdegra@xxxxxxxxxxxxx> wrote:
>> @@ -458,6 +443,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
>> u_domctl)
>>          if ( IS_ERR(d) )
>>          {
>>              ret = PTR_ERR(d);
>> +            d = NULL;
> 
> Considering that in the common code you already set d to NULL,
> is there a specific reason why you do so again here ...
> 
>>              break;
>>          }
>>  
>> @@ -469,39 +455,28 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
>> u_domctl)
>>          op->domain = d->domain_id;
>>          if ( copy_to_guest(u_domctl, op, 1) )
>>              ret = -EFAULT;
>> +        d = NULL;
> 
> ... and here?
> 
> Same further down for XEN_DOMCTL_getdomaininfo.
> 
> Jan
> 
>>      }
>>      break;
>>  
> 
> 
> 

This avoids unlocking the domain when it hasn't been locked (at the
end of the function at domctl_out_unlock) or trying to unlock a
ERR_PTR value.

-- 
Daniel De Graaf
National Security Agency

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