change kernel logging (console=ttyS0) without reboot?

From: Tomasz Chmielewski
Date: Fri Jun 17 2011 - 07:42:33 EST

Generally, most production systems don't like to be restarted unnecessarily.

I was wondering if it's possible to change kernel logging without a restart?

Say, I connected a serial cable to the server, but kernel was not booted with anything like console=ttyS0,19200 in its command line. So anything produced by the kernel will not show up on ttyS0.

Can I still somehow make the kernel to log to ttyS0, without restarting it (I can make syslog do it, but let's assume the syslog crashed and I'm mostly interested in catching a kernel oops/panic etc.)?

Tomasz Chmielewski
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