K 10
svn:author
V 3
mdf
K 8
svn:date
V 27
2010-09-10T21:53:47.185374Z
K 7
svn:log
V 950
MFC r211194, r211229, r212058, r212063: memguard(9) rewrite

r211194:

Rework memguard(9) to reserve significantly more KVA to detect
use-after-free over a longer time.  Also release the backing pages of
a guarded allocation at free(9) time to reduce the overhead of using
memguard(9).  Allow setting and varying the malloc type at run-time.
Add knobs to allow:

 - randomly guarding memory
 - adding un-backed KVA guard pages to detect underflow and overflow
 - a lower limit on the size of allocations that are guarded

r211229:

Fix compile.  It seemed better to have memguard.c include opt_vm.h in
case future compile-time knobs were added that it wants to use.
Also add include guards and forward declarations to vm/memguard.h.

r212058:

The realloc case for memguard(9) will copy too many bytes when
reallocating to a smaller-sized allocation.  Fix this issue.

r212063:

Have memguard(9) crash with an easier-to-debug message on double-free.

END