This commit fixes an issue discovered in the XPMEM registration cache. It
was possible for a registration to be invalidated by multiple threads
leading to a double-free situation or re-use of an invalidated registration.
This commit fixes the issue by setting the INVALID flag on a registation
when it will be deleted. The flag is set while iterating over the tree
to take advantage of the fact that a registration can not be removed
from the VMA tree by a thread while another thread is traversing the VMA
tree.
References #6524
References #7030Closes#6534
Signed-off-by: Nathan Hjelm <hjelmn@google.com>
f86f805be1