kern/116133: Recursive lock panic when w_mtx falls into DELAY

[gavin at FreeBSD.org]

Synopsis: Recursive lock panic when w_mtx falls into DELAY

Responsible-Changed-From-To: kmacy->freebsd-bugs
Responsible-Changed-By: gavin
Responsible-Changed-When: Sun May 29 22:47:50 UTC 2011
Responsible-Changed-Why: 
kmacy has asked for all of his PRs to be reassigned back to the pool.

It is not clear to me whether this is still an issue or not with the
current code.  Due to refactoring, the lock init code is now in
sys/x86/isa/clock.c.  The lock is now marked as MTX_NOPROFILE, it's
not clear to me if this has the same effect on the panic as
MTX_NOWITNESS.

http://www.freebsd.org/cgi/query-pr.cgi?pr=116133