linux-kernel - Re: [PATCH v2] drm/pl111: Use 64-bit arithmetic instead of 32-bit

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <50bd281d-ddfd-4b37-2d0e-6a02985048a4@embeddedor.com>
Date:   Tue, 17 Jul 2018 14:52:01 -0500
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     Eric Anholt <eric@...olt.net>, David Airlie <airlied@...ux.ie>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drm/pl111: Use 64-bit arithmetic instead of 32-bit

Hi Eric,

On 07/17/2018 01:40 PM, Eric Anholt wrote:
> "Gustavo A. R. Silva" <gustavo@...eddedor.com> writes:
> 
>> Add suffix ULL to constant 1000 in order to give the compiler complete
>> information about the proper arithmetic to use.
>>
>> Notice that such constant is used in a context that expects an
>> expression of type u64 (64 bits, unsigned) and the following
>> expression is currently being evaluated using 32-bit arithmetic:
>>
>> mode->clock * 1000
>>
>> Addresses-Coverity-ID: 1466139 ("Unintentional integer overflow")
>> Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>
> 
> This is silly.  The clock won't be over 4ghz -- we haven't seen anything
> over 1024x768 on this hardware as far as I know.  The u64 is for the
> multiplication by width/height below.
> 

Yep. I understand. That's why I didn't use the word *fix* anywhere in
the changelog.

> I've still applied the patch to shut up the tool.
> 

Thanks
--
Gustavo