[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20070716.182853.121295652.davem@davemloft.net>
Date: Mon, 16 Jul 2007 18:28:53 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: ranko@...dernet.net
Cc: kaber@...sh.net, jarkao2@...pl, netdev@...r.kernel.org
Subject: Re: [NET]: gen_estimator deadlock fix
From: Ranko Zivojnovic <ranko@...dernet.net>
Date: Mon, 16 Jul 2007 20:45:05 +0300
> [NET] gen_estimator deadlock fix
>
> -Fixes ABBA deadlock noted by Patrick McHardy <kaber@...sh.net>:
>
> > There is at least one ABBA deadlock, est_timer() does:
> > read_lock(&est_lock)
> > spin_lock(e->stats_lock) (which is dev->queue_lock)
> >
> > and qdisc_destroy calls htb_destroy under dev->queue_lock, which
> > calls htb_destroy_class, then gen_kill_estimator and this
> > write_locks est_lock.
>
> To fix the ABBA deadlock the rate estimators are now kept on an rcu list.
>
> -The est_lock changes the use from protecting the list to protecting
> the update to the 'bstat' pointer in order to avoid NULL dereferencing.
>
> -The 'interval' member of the gen_estimator structure removed as it is
> not needed.
>
> Signed-off-by: Ranko Zivojnovic <ranko@...dernet.net>
Applied, thanks.
-
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists