Messages in this thread | | | Date | Thu, 27 Mar 2008 02:18:12 -0700 | From | Andrew Morton <> | Subject | Re: [Bugme-new] [Bug 10326] New: inconsistent lock state in net_rx_action |
| |
On Thu, 27 Mar 2008 09:55:42 +0100 Jarek Poplawski <jarkao2@gmail.com> wrote:
> On Wed, Mar 26, 2008 at 05:14:03PM -0700, Andrew Morton wrote: > ... > > > >> http://bugzilla.kernel.org/show_bug.cgi?id=10326 > ... > > No, it's not an irq_disable() thing, directly. > > > > What lockdep is saying is that sky2_poll() is taking napi->poll_lock for > > writing with softirqs enabled, but net_rx_action() takes the same lock from > > within softirq context. > > > > If sky2_poll() always takes napi->poll_lock under local_irq_disable() then > > that would be a lockdep bug. > > sky2_poll() doesn't take napi->poll_lock; this lock is taken by > netpoll_poll() before calling sky2_poll(). And before this hardirqs > are disabled in write_msg(). So, theoretically lockdep could be right > if sky2_poll() would enable irqs after this. (If it were done in > netpoll - lockdep should warn before or after sky2_poll() call.) > But I really can't see any such possibility in sky2_poll().
I can't spot it from a five-minute read either. gcc's autoinlining really makes this sort of thing much harder than it used to be :(
Anyway, the accusation is that lockdep is busted, in that it doesn't realise that local_irq_disable() blocks softirqs.
I bet the net code is wrong and we missed it ;)
| |