I'm studying the Server Guide from Ubuntu and I can't resolve this trouble.
I follow these steps:
sudo -s
[sudo] password for ubuntu:
# echo c > /proc/sysrq-trigger
[ 31.659002] SysRq : Trigger a crash
[ 31.659749] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 31.662668] IP: [<ffffffff8139f166>] sysrq_handle_crash+0x16/0x20
[ 31.662668] PGD 3bfb9067 PUD 368a7067 PMD 0
[ 31.662668] Oops: 0002 [#1] SMP
[ 31.662668] CPU 1
I did sudo sysctl -w kernel.sysrq=1
too
But the screen stays frozen and the system doesn't reboot. I can reboot the system manually but after reboot ls /var/crash
returns nothing.
How can I fix this?