[CRIU] [PATCH 0/6] Fix access to /proc on restore

[Pavel Emelyanov]

Saied Kazemi pointed out, that mount namespaces w/o /proc in it
don't get restored. This happens because we frequently access
files using absolute /proc/... paths in restoring code.

This set fixes it by reworking all the places to use proc service
fd (sometimes in quite a tricky manner).

https://bugzilla.openvz.org/show_bug.cgi?id=2984

Thanks,
Pavel