Running $uname -a
Linux linux-h8g6 4.9.0-rc1-2-syzkaller #1 SMP PREEMPT Mon Oct 17 19:37:55 UTC
2016 (55c3dd5) x86_64 x86_64 x86_64 GNU/Linux

with enabled UBSAN (built by GCC 7.0) in qemu, I reached following error:

[   48.723720] UBSAN: Undefined behaviour in
../drivers/gpu/drm/drm_modes.c:325:49
[   48.726943] signed integer overflow:
[   48.728503] 2240 * 1000000 cannot be represented in type 'int'