REGRESSION: rpcrt4_winetest:rpc page faults in heap:RtlFreeHeap[skipped]]

Created an attachment (id=5555)
debuglog

r50029
vbox

Run the rpc winetest suit and you will hit:

(ntoskrnl/mm/mmfault.c:147) Address: deadbee9
Entered debugger on first-chance exception (Exception Code: 0xc0000005) (Page Fault)
Memory at 0xDEADBEE9 could not be read: Page not present.
kdb:> bt
Eip:
<ntdll.dll:a67d>lib/rtl/heap.c:2337 (RtlFreeHeap@12)
Frames:
<rpcrt4.dll:270bf>dll/win32/rpcrt4/rpcrt4_main.c:155 (RpcStringFreeA@4)
<rpcrt4_winetest.exe:ebc1>
<rpcrt4_winetest.exe:1520e>
<rpcrt4_winetest.exe:15423>
<rpcrt4_winetest.exe:15ab5>
<rpcrt4_winetest.exe:15afe>
<kernel32.dll:2e1f2>
<00000000>
kdb:>

***Full debug log attached****