Hi, Am Dienstag, den 21.05.2019, 11:48 +0200 schrieb Oliver Neukum: > On Do, 2019-05-16 at 07:10 +0000, Kloetzke Jan wrote: > > Am Montag, den 06.05.2019, 10:17 +0200 schrieb Oliver Neukum: > > > On So, 2019-05-05 at 00:45 -0700, David Miller wrote: > > > > From: Kloetzke Jan <Jan.Kloetzke@xxxxxxx> > > > > Date: Tue, 30 Apr 2019 14:15:07 +0000 > > > > > > > > > @@ -1431,6 +1432,11 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb, > > > > > spin_unlock_irqrestore(&dev->txq.lock, flags); > > > > > goto drop; > > > > > } > > > > > + if (WARN_ON(netif_queue_stopped(net))) { > > > > > + usb_autopm_put_interface_async(dev->intf); > > > > > + spin_unlock_irqrestore(&dev->txq.lock, flags); > > > > > + goto drop; > > > > > + } > > > > > > > > If this is known to happen and is expected, then we should not warn. > > > > > > > > > > Hi, > > > > > > yes this is the point. Can ndo_start_xmit() and ndo_stop() race? > > > If not, why does the patch fix the observed issue and what > > > prevents the race? Something is not clear here. > > > > Dave, could you shed some light on Olivers question? If the race can > > happen then we can stick to v1 because the WARN_ON is indeed pointless. > > Otherwise it's not clear why it made the problem go away for us and v2 > > may be the better option... > > Hi, > > as Dave confirmed that the race exists, could you resubmit without > the WARN ? Why not just take v1 of the patch? https://lore.kernel.org/netdev/20190417091849.7475-1-Jan.Kloetzke@xxxxxxx/ The original version was exactly the same, just without the WARN_ON(). Or is it required to send a v3 in this case? Regards, Jan