On Thursday, October 22, 2020 12:14 PM, Ville Syrjälä ville.syrjala@linux.intel.com wrote:
On Wed, Oct 21, 2020 at 08:13:43PM -0700, Randy Dunlap wrote:
Hi, With linux-next 20201021, when booting up, I am seeing this: [ 0.560896] UBSAN: signed-integer-overflow in ../drivers/gpu/drm/drm_modes.c:765:20 [ 0.560903] 2376000 * 1000 cannot be represented in type 'int'
Dang. Didn't realize these new crazy >8k modes have dotclocks reaching almost 6 GHz, which would overflow even u32. I guess we'll switch to 64bit maths. Now I wonder how many other places can hit this overflow in practice...
Can you provide an example of a full crazy >8k mode? I'm trying to get a fix for my user-space [1], and I'm wondering if int32_t is enough after dividing by mode->htotal.
CC Pekka, just FYI (I think Weston has similar code).