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

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 19.11.12 at 16:20, Daniel De Graaf <dgdegra@xxxxxxxxxxxxx> wrote:
> 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.

Sorry, this doesn't explain why d needs to be set to NULL twice.

Jan


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