On Mon, Nov 3, 2014 at 3:48 PM, Andy Lutomirski <[email protected]> wrote: > On Mon, Nov 3, 2014 at 3:23 PM, Aditya Kali <[email protected]> wrote: >> On Mon, Nov 3, 2014 at 3:15 PM, Andy Lutomirski <[email protected]> wrote: >>> On Mon, Nov 3, 2014 at 3:12 PM, Aditya Kali <[email protected]> wrote: >>>> On Fri, Oct 31, 2014 at 5:07 PM, Andy Lutomirski <[email protected]> >>>> wrote: >>>>> On Fri, Oct 31, 2014 at 12:19 PM, Aditya Kali <[email protected]> >>>>> wrote: >>>>>> if (opts->flags & CGRP_ROOT_SANE_BEHAVIOR) { >>>>>> pr_warn("sane_behavior: this is still under development >>>>>> and its behaviors will change, proceed at your own risk\n"); >>>>>> - if (nr_opts != 1) { >>>>>> + if (nr_opts > 1) { >>>>>> pr_err("sane_behavior: no other mount options >>>>>> allowed\n"); >>>>>> return -EINVAL; >>>>> >>>>> This looks wrong. But, if you make the change above, then it'll be right. >>>>> >>>> >>>> It would have been nice if simple 'mount -t cgroup cgroup <mnt>' from >>>> cgroupns does the right thing automatically. >>>> >>> >>> This is a debatable point, but it's not what I meant. Won't your code >>> let 'mount -t cgroup -o one_evil_flag cgroup mountpoint' through? >>> >> >> I don't think so. This check "if (nr_opts > 1)" is nested under "if >> (opts->flags & CGRP_ROOT_SANE_BEHAVIOR)". So we know that there is >> atleast 1 option ('__DEVEL__sane_behavior') present (implicit or not). >> Addition of 'one_evil_flag' will make nr_opts = 2 and result in EINVAL >> here. > > But the implicit __DEVEL__sane_behavior doesn't increment nr_opts, right? >
Yes. Hence this change makes sure that we don't return EINVAL when nr_opts == 0 or nr_opts == 1 :) That way, both of the following are equivalent when inside non-init cgroupns: (1) $ mount -t cgroup -o __DEVEL__sane_behavior cgroup mountpoint (2) $ mount -t cgroup cgroup mountpoint Any other mount option will trigger the error here. > --Andy -- Aditya -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
