ls -al /dev/shm (before emerging baselayout) drwxrwxrwt 2 root root 60 Dec 21 17:50 . drwxr-xr-x 23 root root 13780 Dec 21 17:40 .. ls -al /dev/shm (after emerging baselayout) rwxr-xr-x 2 root root 100 Dec 21 13:27 . drwxr-xr-x 23 root root 13820 Dec 21 13:27 .. -rw-r--r-- 1 root root 0 Dec 21 13:27 .keep This is when emerging baselayout 1.12.0_pre12, but it is not the first time I saw it happening. Normal permissions are back after next reboot.
fixed in cvs, thanks for the report also, the reason your /dev/shm seemed to have its permissions "reset" on reboot is that whenever you mount a tmpfs filesystem, it autosets the permissions to 777
