On Wed, Mar 4, 2015 at 6:16 AM, Chris Dunlop <ch...@onthe.net.au> wrote: > On Sat, Feb 28, 2015 at 12:49:31PM +1100, Chris Dunlop wrote: >> On Fri, Feb 27, 2015 at 08:30:42PM -0500, Xu (Simon) Chen wrote: >> > On Fri, Feb 27, 2015 at 6:14 PM, Pravin Shelar <pshe...@nicira.com> wrote: >> > > So it looks like vhost is generating shared skb. Can you try same test >> > > on latest upstream kernel? >> > >> > I don't know whether it's vhost, as for me the VM receiving high volume >> > consistently crashes. >> > >> > I previously had trouble building OVS datapath module on newer kernels. >> > What is the latest kernel that I should try? >> >> According to: >> >> https://github.com/openvswitch/ovs/blob/master/FAQ.md >> >> ...v3.14 *is* the latest kernel supported by the out-of-tree OVS >> kernel module, given that ovs 2.4.x isn't tagged yet and "git >> log v2.3..master" doesn't reveal anything obviously aimed at >> providing >v3.14 compatibility. >> >> Can you try with the in-tree OVS module? > > Simon, I think your crash will be fixed if you cherry-pick this > openvswitch commit (from master) on top of v2.3.1: > > ---------------------------------------------------------------------- > commit d7ff93d7532717ea9d610a7181f24c773170be80 > Author: Andy Zhou <az...@nicira.com> > Date: Fri Aug 29 13:20:23 2014 -0700 > > datapath: simplify sample action implementation > > The current sample() function implementation is more complicated > than necessary in handling single user space action optimization > and skb reference counting. There is no functional changes. > > Signed-off-by: Andy Zhou <az...@nicira.com> > Acked-by: Pravin B Shelar <pshe...@nicira.com> > ---------------------------------------------------------------------- > > The commit isn't actually designed to address the problem directly, > however in simplifying sample() it removes a call to skb_get(). The > skb_get() makes the skb shared, which later causes us to hit the BUG(). > E.g. your v2.3.1 stack trace shows this call path: > > netdev_frame_hook > + netdev_port_receive > | skb is guaranteed not-shared, via: > | skb = skb_share_check(skb, GFP_ATOMIC); > + ovs_vport_receive > + ovs_dp_process_received_packet > + ovs_dp_process_packet_with_key > + ovs_execute_actions > + do_execute_actions > | nla_type(a) == OVS_ACTION_ATTR_SAMPLE > + sample > | skb is made shared here, via: > | sample_skb = skb; > | skb_get(skb); > + do_execute_actions > | nla_type(a) == OVS_ACTION_ATTR_USERSPACE > + output_userspace > + ovs_dp_upcall > + queue_userspace_packet > + skb_checksum_help > + pskb_expand_head > | if (skb_shared(skb)) > | BUG(); BOOM!!! > > > I think commit d7ff93d should be added to v2.3.2 (if indeed that's ever > produced). >
Thanks for investigating the issue. I have backported the patch for branch-2.3. _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss
