linux-3.7.1: disable and reenable NMI watchdog => panic

From: Alexander E. Patrakov
Date: Sun Jan 06 2013 - 12:44:04 EST


As illustrated by the attached screen photo (sorry for bad quality),
disabling and then reenabling the NMI watchdog panics the kernel
(3.7.1). This is reproducible in qemu-kvm as well, but I could not get
the nice panic message to pop up there (most of the time, it just
locks up). This bug is rather important, as laptop-mode-tools, by
default, try to reenable this NMI watchdog when AC power appears, and
this is how I caught the bug the first time.

Alexander E. Patrakov

Attachment: KernelPanic.jpg
Description: JPEG image