Messages in this thread Patch in this message | | | Date | Tue, 16 Oct 2018 23:50:38 -0400 | From | Dave Jones <> | Subject | Re: netconsole warning in 4.19.0-rc7 |
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On Tue, Oct 16, 2018 at 11:40:47PM -0400, Dave Jones wrote:
> > This is exactly what I mentioned in my review here: > > https://marc.info/?l=linux-netdev&m=153816136624679&w=2 > > > > "But irq is disabled here, so not sure if rcu_read_lock_bh() > > could cause trouble... " > > Not sure why this didn't show up for me when I was developing that > patch, but I can now reproduce this. The patch below fixes it for > me, but I'm not sure if there are still any side-effects. > There's also a missed unlock in the error path.
I took another look at that error path. Turns out this is all we need I think..
diff --git a/net/core/netpoll.c b/net/core/netpoll.c index de1d1ba92f2d..f9322d5db899 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -318,6 +318,7 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb, npinfo = rcu_dereference_bh(np->dev->npinfo); if (!npinfo || !netif_running(dev) || !netif_device_present(dev)) { dev_kfree_skb_irq(skb); + rcu_read_unlock_bh(); return; }
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