Re: SoC: linuxolator update: first patch

From: Divacky Roman <xdivac02_at_stud.fit.vutbr.cz>
Date: Tue, 15 Aug 2006 18:27:53 +0200
On Tue, Aug 15, 2006 at 11:49:19AM -0400, John Baldwin wrote:
> 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. :)

it used to be one lock, but it caused more problems then now...

pls, let me fix all the issue and then judge, ok? :)
Received on Tue Aug 15 2006 - 14:30:29 UTC

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