Ramon, thank you for the detailed test case, I was able to run through it exactly as you described, both as root user (see attached) and as nagios (with sudo setup). I suspect I'm unable to reproduce the issue you're seeing since under lxc the /sys/kernel/debug directory belongs to the host and thus is owned by nobody:nogroup, (although I should think that it would produce a permission denied error.)
>From the host: # mount | grep tracing tracefs on /sys/kernel/debug/tracing type tracefs (rw,relatime) In any case, regarding the bug itself, I am able to detect the permissions error: # /usr/lib/nagios/plugins/check_disk -e DISK CRITICAL - /sys/kernel/debug/tracing is not accessible: Permission denied # ls -la /sys/kernel/debug/tracing ls: cannot access '/sys/kernel/debug/tracing': Permission denied # /usr/lib/nagios/plugins/check_disk -e -X tracefs DISK OK| /=44420MB;;;0;3754403 /dev=0MB;;;0;0 /dev/full=0MB;;;0;16018 /dev/null=0MB;;;0;16018 /dev/random=0MB;;;0;16018 /dev/tty=0MB;;;0;16018 /dev/urandom=0MB;;;0;16018 /dev/zero=0MB;;;0;16018 /dev/fuse=0MB;;;0;16018 /dev/net/tun=0MB;;;0;16018 /dev/lxd=0MB;;;0;0 /dev/.lxd-mounts=0MB;;;0;0 /dev/shm=0MB;;;0;16041 /run=16MB;;;0;16041 /run/lock=0MB;;;0;5 /sys/fs/cgroup=0MB;;;0;16041 /var/lib/lxd/shmounts=0MB;;;0;0 /var/lib/lxd/devlxd=0MB;;;0;0 /run/user/1001=0MB;;;0;3208 The suggestion in comment #16 looks like the best approach for addressing the issue so far. Alternatively, I posted a patch to LP #1827159 for altering check_disk itself, however as mentioned in comment #9 on this bug, excluding all tmpfs would be too broad. Ramon, if you can test out the approach outlined in comment #16 and let me know if it seems suitable for your use case, perhaps we should proceed with implementing an SRU for that. ** Attachment added: "Screenshot from 2019-07-17 14-19-10.png" https://bugs.launchpad.net/ubuntu/+source/nagios-plugins/+bug/1516451/+attachment/5277690/+files/Screenshot%20from%202019-07-17%2014-19-10.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1516451 Title: check_disk plugin broken after upgrade to 15.10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/nagios-plugins/+bug/1516451/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs