munmap can cause inconsistent segfaults

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Perform a transaction that privatizes some locations, and then munmap the 
privatized locations non-transactionally.
2. Concurrently execute a speculative transaction that conditionally 
dereferences said locations.
3. Run for a "long time" time.

What is the expected output? 

Results consistent with single-lock semantics.

What do you see instead?

Segmentation faults from the speculative transactions due to privatization 
safety violations.

Workaround?

Perform all munmap operations inside [[relaxed]] transactions.

Original issue reported on code.google.com by [email protected] on 11 Jul 2011 at 5:02