Re: [syzbot] WARNING in iomap_iter

Siddh Raman Pant
2022-08-21T11:28:42Z

On Sun, 21 Aug 2022 11:59:05 +0530 Christoph Hellwig wrote:
> On Thu, Aug 18, 2022 at 08:51:16PM +0530, Siddh Raman Pant wrote:
> > On Thu, 18 Aug 2022 20:20:02 +0530 Matthew Wilcox wrote:
> > > I don't think changing these from u64 to s64 is the right way to go.
> >
> > Why do you think so? Is there somnething I overlooked?
> >
> > I think it won't intorduce regression, since if something is working,
> > it will continue to work. If something does break, then they were
> > relying on overflows, which is anyways an incorrect way to go about.
>
> Well, for example userspace code expecting unsignedness of these
> types could break. So if we really think changing the types is so
> much preferred we'd need to audit common userspace first. Because
> of that I think the version proposed by willy is generally preferred.

Alright.

> > Also, it seems even the 32-bit compatibility structure uses signed
> > types.
>
> We should probably fix that as well.

Isn't having signed type how it is should be though? Or do you mean need
to fix assignment in the conversions (like in loop_info64_from_compat)?

Thanks,
Siddh