8.5.2 Alt-SysRq

Insurance against system malfunction is provided by the kernel compile option "Magic SysRq key". Pressing Alt-SysRq on an i386, followed by one of the keys r 0 k e i s u b, does the magic.

Un`r'aw restores the keyboard after things like X crashes. Changing the console loglevel to `0' reduces error messages. sa`k' (system attention key) kills all processes on the current virtual console. t`e'rminate kills all processes on the current terminal except init. k`i'll kills all processes except init.

`S'ync, `u'mount, and re`b'oot are for getting out of really bad situations.

Debian default installation kernels are not compiled with this option at the time this document is written. Recompile the kernel to activate this function. Detailed information is in /usr/share/doc/kernel-doc-version/Documentation/sysrq.txt.gz or /usr/src/kernel-version/Documentation/sysrq.txt.gz.