On Mon, Oct 29, 2007 at 09:26:11PM -0700, David Miller wrote: > From: Tina Yang <[EMAIL PROTECTED]> > Date: Tue, 16 Oct 2007 22:46:30 -0700 > > > The precise race is > > 1) net_rx_action get the dev from poll_list > > 2) at the same time, netpoll poll_napi() get a hold of the poll lock > > and calls ->poll(), remove dev from the poll list > > 3) after it finishes, net_rx_action get the poll lock, and calls > > ->poll() the second time, and panic when trying to remove (again) > > the dev from the poll list. > > This is trivial to fix. > > I'll check the following into 2.6.14 and backport it to > the -stable trees. > > [NET]: Fix race between poll_napi() and net_rx_action() > > netpoll_poll_lock() synchronizes the ->poll() invocation > code paths, but once we have the lock we have to make > sure that NAPI_STATE_SCHED is still set. Otherwise we > get: > > cpu 0 cpu 1 > > net_rx_action() poll_napi() > netpoll_poll_lock() ... spin on ->poll_lock > ->poll() > netif_rx_complete > netpoll_poll_unlock() acquire ->poll_lock() > ->poll() > netif_rx_complete() > CRASH > > Based upon a bug report from Tina Yang. > > Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
Thanks, Dave. -- Mathematics is the supreme nostalgia of our time. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
