IPC semaphores: anyone used them?

[Chris Metcalf]

I'm trying to use the SysV semaphore stuff (semget, semctl, semop) on a
variety of Sun 4s running SunOS 4.1.  Certain calls to semop() pretty
nearly crash the machine (in particular, a call with two sembufs with a
positive and a negative sem_op will do this).  The result is that the
window system freezes and no new processes are forked:  a remote xload
will keep going, and inetd will hand out sockets, but you can't do
anything more without a reboot.

Has anyone used the semaphore stuff, and (possibly) seen this?  Is it a
bug in 4.1?

Thanks very much!

Chris Metcalf, MIT Laboratory for Computer Science
metcalf at masala.lcs.mit.edu // (617) 253-7766