Linus Torvalds Uses AI to Crack a Nasty GPU Bug

Linus Torvalds spent much of a day hunting a GPU-related bug in the Linux kernel that had been present for about two years. The symptom: on certain Intel Arc graphics cards, cold-booting into a Linux desktop could lead to a black screen with no crash or kernel panic—gdm, the GNOME login manager, repeatedly restarted while the compositor failed to draw. Torvalds traced the issue to a memory boundary calculation inside a function that rounds an address to the nearest 128 kilobytes. In one scenario, the driver treated a gap of roughly two kilobytes as free VRAM, but Mesa’s page tables landed there, getting overwritten by compression hardware and causing a crash loop. An AI assistant helped with debug work.