Comment 1 for bug 1692543

This is caused do a change made upstream in the 4.11 kernel, which forbids writing the buffer size parameter after boot. The change to boot time preallocated work buffers made this parameter useless, but 4.11 only partially merged that work, making writing the buffer size an attack vector on the kernel memory and with user namespaces enabled any user could exploit it. Hence a follow-on patch to make the buffer size read-only after boot.

We have 2 choices for dealing with this, either fix the regression tests OR we can virtualize the buffer size parameter per namespace, capping the virtualized size by what was allocated at boot.