In the Linux kernel, the following vulnerability has been resolved:
drm/exynos: exynos7drmdecon: add vblank check in IRQ handling
If there's support for another console device (such as a TTY serial), the kernel occasionally panics during boot. The panic message and a relevant snippet of the call stack is as follows:
Unable to handle kernel NULL pointer dereference at virtual address 000000000000000 Call trace: drmcrtchandlevblank+0x10/0x30 (P) deconirq_handler+0x88/0xb4 [...]
Otherwise, the panics don't happen. This indicates that it's some sort of race condition.
Add a check to validate if the drm device can handle vblanks before calling drmcrtchandle_vblank() to avoid this.