Example fails on today's Ubuntu 13.04 daily

Example fails on today's Ubuntu 13.04 daily

Posted Mar 7, 2013 13:42 UTC (Thu) by BernardB (subscriber, #47903)
Parent article: Namespaces in operation, part 5: User namespaces

No luck trying this out on today's Ubuntu 13.04 daily build:

$ id
uid=1000(bernard) gid=1000(bernard)
$ uname -a
Linux dev32 3.8.0-11-generic #20-Ubuntu SMP Tue Mar 5 20:33:22 UTC 2013 i686 athlon i686 GNU/Linux
$ gcc -o demo_userns demo_userns.c  -lcap
$ ./demo_userns
clone: Invalid argument
$ sudo ./demo_userns # It was worth a shot!
clone: Invalid argument
$ strace -e clone ./demo_userns 
clone(child_stack=0x814a064, flags=0x10000000|SIGCHLD) = -1 EINVAL (Invalid argument)
clone: Invalid argument
$ apt-cache policy linux-image-`uname -r`
linux-image-3.8.0-11-generic:
  Installed: 3.8.0-11.20
  Candidate: 3.8.0-11.20
  Version table:
 *** 3.8.0-11.20 0
        500 http://gb.archive.ubuntu.com/ubuntu/ raring/main i386 Packages
        100 /var/lib/dpkg/status

I've yet to delve into the kernel source to find where EINVAL is coming from, but can anyone see if I am missing something obvious? Or maybe it's because Ubuntu's done something magic to their kernel? (The Makefile in their Linux sources purports to be 3.8.2).

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