Hi, I have encountered a strange bug (on 3.14, 3.16.3 and master) regarding mount namespaces and a particular directory. Somehow, mounts are being mounted successfully but disappearing when the process dies, but only for /mnt/puppy, not for any other directory in the system: # grep puppy /proc/mounts # nothing mounted yet # mount -t tmpfs tmpfs /mnt/puppy # grep puppy /proc/mounts # no output # mount -t tmpfs tmpfs /mnt/puppy2 # grep puppy /proc/mounts tmpfs /mnt/puppy2 tmpfs rw,relatime 0 0 Furthermore, I wrote a program to mount /mnt/puppy and immediately read /proc/mounts: # grep puppy /proc/mounts # no output # ./mounter tmpfs /mnt/puppy tmpfs rw,relatime 0 0 # grep puppy /proc/mounts # no output Finally, I note that the problem seems to occur if the mount needs to be propagated to the default namespace (note that systemd causes namespaces to be shared by default): # unshare -m subshell # mount -t tmpfs tmpfs /mnt/puppy subshell # grep puppy /proc/mounts # no output subshell # mount --make-rprivate / subshell # mount -t tmpfs tmpfs /mnt/puppy subshell # grep puppy /proc/mounts # success! tmpfs /mnt/puppy tmpfs rw,relatime 0 0 subshell # umount /mnt/puppy subshell # exit # mount --make-rprivate / # back in the default namespace # mount -t tmpfs tmpfs /mnt/puppy # grep puppy /proc/mounts # no output I hope someone has an idea of what's going on or how to debug this because I've run out of ideas... Thanks! -- Ross Lagerwall -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
