Re: [PATCH][next] driver core: platform: fix u32 greater or equal to zero comparison

From: Dan Carpenter
Date: Thu Jan 16 2020 - 23:44:59 EST


On Fri, Jan 17, 2020 at 07:42:16AM +0300, Dan Carpenter wrote:
> On Thu, Jan 16, 2020 at 05:57:58PM +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> >
> > Currently the check that a u32 variable i is >= 0 is always true because
> > the unsigned variable will never be negative, causing the loop to run
> > forever. Fix this by changing the pre-decrement check to a zero check on
> > i followed by a decrement of i.
> >
> > Addresses-Coverity: ("Unsigned compared against 0")
> > Fixes: 39cc539f90d0 ("driver core: platform: Prevent resouce overflow from causing infinite loops")
>
> A better fix would be to revert this patch. It doesn't fix a real bug.
> The ->num_resources is typically under 5. It's not going to overflow
> INT_MAX any time soon. There are "architectures with smaller ints."

I left out a word. There are *no* "architectures with smaller ints."...

I mean there used to be systems with 16 bit int but that was before I
was born. You could never run linux on them.

regards,
dan carpenter