Date: Tue, 15 Aug 2006 11:49:19 -0400 From: John Baldwin <jhb@freebsd.org> To: Suleiman Souhlal <ssouhlal@freebsd.org> Cc: emulation@freebsd.org, freebsd-current@freebsd.org Subject: Re: SoC: linuxolator update: first patch Message-ID: <200608151149.20338.jhb@freebsd.org> In-Reply-To: <44E1E64F.6020205@FreeBSD.org> References: <20060814170418.GA89686@stud.fit.vutbr.cz> <200608151101.30951.jhb@freebsd.org> <44E1E64F.6020205@FreeBSD.org>
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On Tuesday 15 August 2006 11:20, Suleiman Souhlal wrote:
> John Baldwin wrote:
> >
> >>+ KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n"));
> >>+ }
> >>+
> >>+ em->child_clear_tid = NULL;
> >>+ em->child_set_tid = NULL;
> >>+
> >>+ /* allocate the shared struct only in clone()/fork cases
> >>+ * in the case of clone() td = calling proc and child = pid of
> >>+ * the newly created proc
> >>+ */
> >>+ if (child != 0) {
> >>+ if (flags & CLONE_VM) {
> >>+ /* lookup the parent */
> >>+ p_em = em_find(td->td_proc, EMUL_LOCKED);
> >>+ KASSERT(p_em != NULL, ("proc_init: parent emuldata not found for
> >>CLONE_VM\n"));
> >>+ em->shared = p_em->shared;
> >>+ em->shared->refs++;
> >>
> >>This is unsafe. Please use the functions in sys/refcount.h.
> >
> >
> > Well, in this case he's already holding a lock. If he always holds a lock
> > when accessing and modifying refs, then refcount_*() would only add
overhead.
>
> Isn't he holding the wrong lock (emul_lock vs emul_shared_lock)?
Maybe. I think those should be merged into one lock anyway. :)
--
John Baldwin
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