shm_open (667) & locking_init(174), not 2.3.xx kernel

[Peter Samuelson]

[Joel Burton <joel at scw.org>]
> This weekend, we upgraded our server to Linux-Mandrake 7.1, which
> uses a (slightly customized by Mandrake) 2.2.15 kernel. Since then,
> users are unable to log in, and log.smb shows
> 
> locking/shmem_sysv_shm_open(667). Can't create or use use IPC area. Error
> was File exists
> locking/locking.c:locking_init(174). ERROR: Failed to initialise share
> modes

Hmmmmmmmm.  You're right, this has nothing to do with the 2.3.x problem
you've heard about.  (That problem is very specific to 2.3/2.4, a side
effect of Al Viro's recent reorganization of half the VFS.)

According to `man shmget',

       EEXIST      is   returned  if  IPC_CREAT  |  IPC_EXCL  was
                   specified and the segment exists.

This is happening in `locking/shmem_sysv.c' where it fails to create
the shm segment after it has failed to open an existing one.

My guess is that the segment exists.  Stop Samba, type `ipcs' and see
if shared memory segment 0x280267 is sitting around.  If so, remove it
with `ipcrm 0x280267'.  Then restart Samba.

Peter