Subject: Re: Problem with gcore and permissions
To: D'Arcy J.M. Cain <>
From: Allen Briggs <>
List: tech-kern
Date: 01/17/2005 22:36:28
On Mon, Jan 17, 2005 at 05:22:47PM -0500, D'Arcy J.M. Cain wrote:
> It's possible that I have identified the change that fixes this.  In
> src/sys/kern/sysv_sem.c the following was pulled up in ticket #903. 
> Could this be the critical change?

Attempting to use SysV semaphores, using an algorithm in Stevens' UNPv2 
to prevent a race condition, will cause the code to go into an infinite
loop without this change.  The algorithm depends on sem_otime being
updated with the time of the last semop(), but that doesn't happen in
the old code (this has always been broken).

I was kind of surprised to find it, but there it is...


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