Skip to main content.

Features sometimes misconstrued as bugs


Rebooting a host that's the recipient of a target machine's serial console output drops the target machine into the kernel debugger (top)

This isn't actually a crash, rather shutting down the serial console host caused the BREAK character to be sent to the target. This drops system to ddb(4) by default. Typing c (for continue) at the ddb prompt when next time connected will resume the target's kernel.

One way to avoid this is to set sysctl ddb.fromconsole=0, or change sysctl hw.cnmagic to something else (see sysctl(8)).