What steps will reproduce the problem?
1. Alter $GOROOT/src/pkg/runtime/malloc.goc to reflect changes shown here
http://groups.google.com/group/golang-nuts/msg/1a29ca2e2ac295b3 and build

2. Build and run go code here
http://groups.google.com/group/golang-nuts/msg/6b35978950ab9038

What is the expected output?
0

What do you see instead?
unexpected fault address 0x343f0e0
throw: fault

[signal 0xb code=0x1 addr=0x343f0e0 pc=0x406417]

panic during panic

Which compiler are you using (5g, 6g, 8g, gccgo)?
6g

Which operating system are you using?
Linux/Ubuntu 10.04.3

Which revision are you using?  (hg identify)
3c21f37b25a3+ weekly/weekly.2011-07-19

Please provide any additional information below.