Initially I thought this was a small issue but eventually after the system boots up, I couldn’t restart the system with reboot, shutdown, nor init 6. It would stuck/freeze/hang at the “Uptime: …” line and before the “Rebooting..” line. I tried with 2 other barebones thinking that it is hardware issue, I got same results though. Clearly this is a bug in FreeBSD 6.3-RELEASE’s kernel.

I tried installing FreeBSD 6.4-RELEASE (32-bit) and it restarted properly. I was going to update the system to 6.3-STABLE — the server has to run 6.3, as 6.4 is not acceptable yet due to software compatibility issues — to see if the issue has been addressed in the -STABLE branch, but when I tried recompiling the kernel with PAE (in addition to SMP) support (still using -RELEASE kernel source tree), the reboot problem disappeared. YAY! I got it the fix by accident!

I’m not sure what is wrong since similar reboot problem seems to be popping around randomly since FreeBSD 5.X (after doing some Google searches). Browsing the PR database of FreeBSD didn’t help much either. Maybe if you know exactly what is wrong, you can share it here to help others with similar problem.