Re: Coverity: z_erofs_handle_inplace_io(): Uninitialized variables

[Kees Cook <keescook@chromium.org>]

On Fri, Apr 09, 2021 at 09:01:46AM +0800, Gao Xiang wrote:
> Hi,
> 
> On Thu, Apr 08, 2021 at 05:09:14PM -0700, coverity-bot wrote:
> > Hello!
> > 
> > This is an experimental semi-automated report about issues detected by
> > Coverity from a scan of next-20210408 as part of the linux-next scan project:
> > https://scan.coverity.com/projects/linux-next-weekly-scan
> > 
> > You're getting this email because you were associated with the identified
> > lines of code (noted below) that were touched by commits:
> > 
> >   Wed Apr 7 13:17:55 2021 +0800
> >     c660a3a86e7e ("erofs: support decompress big pcluster for lz4 backend")
> > 
> > Coverity reported the following:
> > 
> > *** CID 1503704:  Uninitialized variables  (UNINIT)
> > /fs/erofs/decompressor.c: 160 in z_erofs_handle_inplace_io()
> > 154     	}
> > 155     	kunmap_atomic(inpage);
> > 156     	might_sleep();
> > 157     	while (1) {
> > 158     		src = vm_map_ram(rq->in, nrpages_in, -1);
> > 159     		/* retry two more times (totally 3 times) */
> > vvv     CID 1503704:  Uninitialized variables  (UNINIT)
> > vvv     Using uninitialized value "i".
> > 160     		if (src || ++i >= 3)
> > 161     			break;
> > 162     		vm_unmap_aliases();
> > 163     	}
> > 164     	*maptype = 1;
> > 165     	return src;
> 
> Thanks for the report!
> 
> This bug was reported by Colin King before (next-20210407), and has already
> been fixed in (next-20210408), see:
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/fs/erofs/decompressor.c?h=next-20210408#n157
> and
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/fs/erofs/internal.h?h=next-20210408#n405

Ah-ha, thank you! Colin is fast. :)

-- 
Kees Cook