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Namespaces in operation, part 6: more on user namespaces

Posted Mar 8, 2013 17:07 UTC (Fri) by alexl (subscriber, #19068)
Parent article: Namespaces in operation, part 6: more on user namespaces

I tried this in the latest Fedora kernel (3.8.1-201.fc18.x86_64), but it seems the user namespaces doesn't work:

./userns_child_exec -U
clone: Invalid argument

strace says:
clone(child_stack=0x7020f0, flags=CLONE_NEWUSER|SIGCHLD) = -1 EINVAL (Invalid argument)

Isn't this supposed to work in 3.8.1?

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Namespaces in operation, part 6: more on user namespaces

Posted Mar 8, 2013 19:47 UTC (Fri) by ebiederm (subscriber, #35028) [Link]

cat /proc/config.gz | grep USER_NS

Were user namespaces enabled?

I expect the generic fedora build enables one of the filesystems that has not had a kuid/kgid conversion in 3.8 and thus can not enable user namespaces.

Namespaces in operation, part 6: more on user namespaces

Posted Mar 8, 2013 20:58 UTC (Fri) by mathstuf (subscriber, #69389) [Link]

Looking at the config in the kernel srpm, the user namespace isn't supported even in Rawhide yet (3.9.0-rc1).

Namespaces in operation, part 6: more on user namespaces

Posted Mar 8, 2013 22:28 UTC (Fri) by ebiederm (subscriber, #35028) [Link]

I suspect it will have to wait until 3.10 when XFS stops turning off user namespaces.

Namespaces in operation, part 6: more on user namespaces

Posted Mar 8, 2013 23:07 UTC (Fri) by mathstuf (subscriber, #69389) [Link]

I was actually planning on building my own kernel RPM with user namespaces this weekend. I don't use XFS anywhere, so I'm fine with the tradeoff.