kern/63662: Using read-only NULLFS leads to panic. gdb output included, easy to reproduce.

[Tim J. Robbins]

Synopsis: Using read-only NULLFS leads to panic. gdb output included, easy to reproduce.

Responsible-Changed-From-To: freebsd-bugs->tjr
Responsible-Changed-By: tjr
Responsible-Changed-When: Mon Mar 8 16:05:48 PST 2004
Responsible-Changed-Why: 
I will MFC the fix.

http://www.freebsd.org/cgi/query-pr.cgi?pr=63662