Re: NOHZ: local_softirq_pending 08

From: Tilman Schmidt
Date: Thu Oct 22 2009 - 19:38:19 EST


On 21.10.2009 20:46, /me wrote:
>>>> I have encountered the message in the subject during a test of
>>>> the Gigaset CAPI driver, and would like to determine whether
>>>> it's a bug in the driver, a bug somewhere else, or no bug at
>>>> all. The test scenario was PPP over ISDN with pppd+capiplugin.
>>>> In an alternative scenario, also PPP over ISDN but with
>>>> smpppd+capidrv, the message did not occur.
>
> I'm sorry, I had confused the two cases. The message occurs in
> the smpppd+capidrv scenario, not with pppd+capiplugin.
>
>>>> Johannes' answer pointed me to the netif_rx() function.
>>>> The Gigaset driver itself doesn't call that function at all.
>>>> In the scenario where I saw the message, it was the SYNC_PPP
>>>> line discipline that did.
>
> This analysis was therefore wrong. It would be the netif_rx()
> call towards the end of isdn_ppp_push_higher() in
> drivers/isdn/i4l/isdn_ppp.c L1177.

Having noticed that, I cooked up the following patch which fixed
the messages for me. Comments? (Adding i4l people to the already
impressive CC list.)

--- 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);
/* net_dev->local->stats.rx_packets++; done in isdn_net.c */
return;



--
Tilman Schmidt E-Mail: tilman@xxxxxxx
Bonn, Germany
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