cvs commit: src/sys/vm vm_fault.c

[Brian Fundakowski Feldman]

On Sat, Aug 21, 2004 at 11:39:55PM -0400, Brian Fundakowski Feldman wrote:
> On Sat, Aug 21, 2004 at 10:30:03PM -0400, Robert Watson wrote:
> > 
> > On Sat, 21 Aug 2004, Brian Fundakowski Feldman wrote:
> > 
> > > > > #1. Lock order reversal.  Giant is acquired after the map read lock.
> > > > 
> > > > No, that is the order it has been in for months.  The other functions
> > > > that acquire a map lock and Giant do the same.
> > > 
> > > Giant can never be acquired after another lock has been acquired :-(
> > 
> > Actually, that's not quite accurate.  Take a look at the relationship
> > between lockmgr/sx locks and Giant, for example.
> 
> Point taken.  This is the first time I've seen Giant in a lock order
> reversal with vm locks, though, and I've been running WITNESS for years.

Also, it was the system_map lock, so it was a mutex, not an sx.

/Goes back to trying to figure out wtf portupgrade -rR kde\* keeps causing
 hangs, but only in X, not at the command line, and not seemingly
 dependant on AGP/X driver.

-- 
Brian Fundakowski Feldman                           \'[ FreeBSD ]''''''''''\
  <> green at FreeBSD.org                               \  The Power to Serve! \
 Opinions expressed are my own.                       \,,,,,,,,,,,,,,,,,,,,,,\