alc e7f49ffe6f Handle a race between pmap_kextract() and pmap_promote_pde(). This race is
known to cause a kernel crash in ZFS on i386 when superpage promotion is
enabled.

Tested by:	netchild
MFC after:	1 week
2010-01-23 18:42:28 +00:00
..
2010-01-19 15:31:18 +00:00