Date: Wed, 4 Mar 2009 09:34:40 -0800 (PST) From: Barney Cordoba <barney_cordoba@yahoo.com> To: jhb@freebsd.org Cc: current@freebsd.org Subject: Re: MTX Lock implementation question Message-ID: <415008.75717.qm@web63902.mail.re1.yahoo.com> In-Reply-To: <200903041013.22496.jhb@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
--- On Wed, 3/4/09, John Baldwin <jhb@freebsd.org> wrote:
> From: John Baldwin <jhb@freebsd.org>
> Subject: Re: MTX Lock implementation question
> To: freebsd-current@freebsd.org, barney_cordoba@yahoo.com
> Cc: current@freebsd.org
> Date: Wednesday, March 4, 2009, 10:13 AM
> On Wednesday 04 March 2009 7:54:32 am Barney Cordoba wrote:
> >
> > Suppose the following:
> >
> > Module foo.c
> >
> > foo_getlock(sc)
> > {
> > FOO_LOCK(sc);
> > }
> > foo_unlock(sc)
> > {
> > FOO_UNLOCK(sc);
> > }
> > foo_dosomething(sc)
> > {
> > MTX_LOCK_ASSERT(sc);
> > foo_dooit();
> > }
> >
> > Module bar.c
> >
> > bar_dofoo()
> > {
> > foo_getlock(sc);
> > foo_dosomething(sc);
> > foo_unlock(sc);
> > }
>
> This works fine.
>
> > Is this something that shouldn't work? I need to
> access functions
> > that require locks in a different module, but this
> code barfs on
> > ASSERT with witness enabled. Is this a deflugalty in
> WITNESS, or do
> > I need to create functions within foo that do the
> locking? Its been
> > working ok for awhile (its not a high volume function)
> but when I
> > fired up witness to debug something else I encountered
> witness panics.
>
> You probably have a real bug that WITNESS is warning about
> however.
>
> --
> John Baldwin
It seems that theres a problem when the mutex is initialized with a type
of NULL. Changing it to a non-null string eliminated the issue. I'm
running a 7.0 base system.
Barney
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?415008.75717.qm>