You must be in text mode to enter the kernel debugger (kadb). So, first exit any window system.
The kadb: prompt is displayed.
Type the following commands at the kadb: prompt.
Press <F1-a> kadb: vfs_syncall/W ffffffff kadb: 0>eip kadb: :c kadb: :c kadb: :c
After you type the first :c , the system panics, so you need to type :c again. The system panics again, so type :c a third time to force the crash dump and reboot the system.
After the crash dump is written to disk, the system continues to reboot.
Verify that the system has rebooted by logging in at the console login prompt.