Re: [PATCH] net: orphan queued skbs if device tx can stall

From: Herbert Xu
Date: Sun Apr 08 2012 - 19:50:06 EST


On Sun, Apr 08, 2012 at 08:13:25PM +0300, Michael S. Tsirkin wrote:
> commit 0110d6f22f392f976e84ab49da1b42f85b64a3c5
> tun: orphan an skb on tx
> Fixed a configuration where skbs get queued
> at the tun device forever, blocking senders.
>
> However this fix isn't waterproof:
> userspace can control whether the interface
> is stopped, and if it is, packets
> get queued in the qdisc, again potentially forever.
>
> Complete the fix by setting a private flag and orphaning
> at the qdisc level.
>
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>

1) Doesn't this break local UDP push-back?
2) Isn't the stall a bug in the backend and isn't this just
papering over that?

Cheers,
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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