The reverse case of this race (you must msync before read) is
well known. This is the not so common one.

It can be triggered only on systems which do a lot of task
switching and only at UML startup. If you are starting 200+ UMLs
~ 0.5% will always die without this fix.
Signed-off-by: NAnton Ivanov <antivano@cisco.com>
[rw: minor whitespace fixes]
Signed-off-by: NRichard Weinberger <richard@nod.at>