[Doodman]

I'm assuming on linux.

Stop world and zones.

Check for shared memory segments:

% ipcs -m

------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status      
0x49056d82 4980740    doodman   600        16400909   0

If there is one, and nattach is 0, remove it:

% ipcrm -m 4980740

Shutting down world/zones doesn't clean up shared memory properly, sometimes you need to remove it yourself.