[linux-sunxi] [PATCH 2/4] simplefb: Add support for enumerating simplefb dt nodes in /chosen

[Julian Calaby]

Hi Hans,

On Thu, Nov 13, 2014 at 7:40 PM, Hans de Goede <hdegoede at redhat.com> wrote:
> Hi,
>
> On 11/13/2014 09:34 AM, Geert Uytterhoeven wrote:
>> Hi Hans,
>>
>> On Thu, Nov 13, 2014 at 9:27 AM, Hans de Goede <hdegoede at redhat.com> wrote:
>>>>> +       char name[16];
>>>>> +       struct device_node *np;
>>>>> +
>>>>> +       ret = platform_driver_register(&simplefb_driver);
>>>>> +       if (ret)
>>>>> +               return ret;
>>>>> +
>>>>> +       for (i = 0; ; i++) {
>>>>> +               snprintf(name, sizeof(name), "framebuffer%d", i);
>>>>
>>>> This smells like an infinite loop: we can be pretty sure that no
>>>> hardware will ever exist with more than 9999 (I think?) framebuffers,
>>>> however if that ever happens this'll loop until it runs out of RAM.
>>>> Maybe add a suitably high limit to the for loop?
>>>
>>> The loop will stop as soon as there are no more framebuffer# nodes in chosen,
>>> so the loop is only infinite if there are infinite nodes in the devicetree,
>>> which would make the devicetree infinitely large, so this will never happen.
>>
>> If there are 10000 frame buffers, the loop will continue beyond that,
>> as the index will be truncated to 4 digits due to the size of name[].
>> It will stop when (signed) i becomes negative, though ;-)
>>
>> One solution is to increase the size of name[],
>
> This is probably never going to happen, but I'll increase the size of name in v2
> anyways.

You could also just limit it to 100 or something like that.

Thanks,

-- 
Julian Calaby

Email: julian.calaby at gmail.com
Profile: http://www.google.com/profiles/julian.calaby/