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

[Hans de Goede <hdegoede@redhat.com>]

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@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.

Regards,

Hans