Kernel panic

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Kernel panic is when something is extremely bad happens that the kernel gives up and panics. This is typically caused by software such as Sun's Java Virtual Machine.

The Trick: Reboot automatically when the kernel panics[edit | edit source]

You can make the kernel reboot automatically instead of halting (the default behavoir) if/when the kernel panics.

You can set this by sending a message to /proc (as root):

echo 5 >/proc/sys/kernel/panic

The value given is seconds to wait before rebooting. The default setting is 0, which doesn't cause a reboot.

To check the current settings:

cat /proc/sys/kernel/panic

You can also add:

kernel.panic=5

to the file /etc/sysctl.conf

It's also possible to do this by adding panic=5 to the boot-loader command-line. This is good in the few rare cases (suck as boot with a bad initrd) where the kernel can panic before reading /etc/sysctrl.conf.

Only on oops[edit | edit source]

It's also possible to set a different waiting time before rebooting on oops panics by giving a value to /proc/sys/kernel/panic_on_oops.