lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 09 Jan 2013 09:54:59 +0800 From: Wanlong Gao <gaowanlong@...fujitsu.com> To: Rusty Russell <rusty@...tcorp.com.au> CC: linux-kernel@...r.kernel.org, "Michael S. Tsirkin" <mst@...hat.com>, Jason Wang <jasowang@...hat.com>, Eric Dumazet <erdnetdev@...il.com>, virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org, Wanlong Gao <gaowanlong@...fujitsu.com> Subject: Re: [PATCH V3 1/2] virtio-net: fix the set affinity bug when CPU IDs are not consecutive On 01/09/2013 07:31 AM, Rusty Russell wrote: > Wanlong Gao <gaowanlong@...fujitsu.com> writes: >> */ >> static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb) >> { >> - int txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) : >> - smp_processor_id(); >> + int txq = 0; >> + >> + if (skb_rx_queue_recorded(skb)) >> + txq = skb_get_rx_queue(skb); >> + else if ((txq = per_cpu(vq_index, smp_processor_id())) == -1) >> + txq = 0; > > You should use __get_cpu_var() instead of smp_processor_id() here, ie: > > else if ((txq = __get_cpu_var(vq_index)) == -1) > > And AFAICT, no reason to initialize txq to 0 to start with. > > So: > > int txq; > > if (skb_rx_queue_recorded(skb)) > txq = skb_get_rx_queue(skb); > else { > txq = __get_cpu_var(vq_index); > if (txq == -1) > txq = 0; > } Got it, thank you. > > Now, just to confirm, I assume this can happen even if we use vq_index, > right, because of races with virtnet_set_channels? I still can't understand this race, could you explain more? thank you. Regards, Wanlong Gao > > while (unlikely(txq >= dev->real_num_tx_queues)) > txq -= dev->real_num_tx_queues; > > > Thanks, > Rusty. > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists