cvs commit: src/sys/kern kern_umtx.c

[Jeff Roberson]

On Sun, 25 May 2003, Alan L. Cox wrote:

> Jeff Roberson wrote:
> >
> > jeff        2003/05/25 11:18:32 PDT
> >
> >   FreeBSD src repository
> >
> >   Modified files:
> >     sys/kern             kern_umtx.c
> >   Log:
> >    - Create a new lock, umtx_lock, for use instead of the proc lock for
> >      protecting the umtx queues.  We can't use the proc lock because we need
> >      to hold the lock across calls to casuptr, which can fault.
> >
> >   Approved by:    re
> >
> >   Revision  Changes    Path
> >   1.3       +13 -6     src/sys/kern/kern_umtx.c
>
> In general, we can sleep on a fault.  Thus, you could be holding this
> mutex at the time of a sleep.
>

That was just pointed out to me.  This patch at least makes things
slightly more correct.

I'm going to have to look at the problem a little closer to see if I can
implement this code without holding a lock across the casuptr.  otherwise
I'll have to use sx.

Cheers,
Jeff