On Fri, 2009-10-23 at 16:27 +0200, Tilman Schmidt wrote: > >> --- a/drivers/isdn/i4l/isdn_ppp.c > >> +++ b/drivers/isdn/i4l/isdn_ppp.c > >> @@ -1174,7 +1174,10 @@ isdn_ppp_push_higher(isdn_net_dev * net_dev, isdn_net_local * lp, struct sk_buff > >> #endif /* CONFIG_IPPP_FILTER */ > >> skb->dev = dev; > >> skb_reset_mac_header(skb); > >> - netif_rx(skb); > >> + if (in_interrupt()) > >> + netif_rx(skb); > >> + else > >> + netif_rx_ni(skb); > > > > So you've verified that the entire i4l stack can cope with being called > > twice on the same CPU, from different contexts? > > What makes you think so? I thought I'd explained this in my other email. *sigh* You're squelching a warning, which comes from the fact that you're calling something that calls into netif_rx() with softirqs enabled. That would seem to imply that potentially a softirq could at the same time call into that code too. Basically, what happens now is this: disable softirqs call into i4l/ppp i4l/ppp code call netif_rx() more code enable softirqs You're changing it to call into i4l/ppp i4l/ppp code call netif_rx_ni() more code so the entire chunks "i4l/ppp code" and "more code" are now no longer protected against being interrupted by a softirq that runs the same code, maybe for a different device, on the same CPU. johannes
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