On 4/21/17 2:34 PM, Robert Shearman wrote:
> David reported that doing the following:
>
> ip li add red type vrf table 10
> ip link set dev eth1 vrf red
> ip addr add 127.0.0.1/8 dev red
> ip link set dev eth1 up
> ip li set red up
> ping -c1 -w1 -I red 127.0.0.1
> ip li del red
>
> when either policy routing IP rules are present or the local table
> lookup ip rule is before the l3mdev lookup results in a hang with
> these messages:
>
> unregister_netdevice: waiting for red to become free. Usage count = 1
>
> The problem is caused by caching the dst used for sending the packet
> out of the specified interface on a local route with a different
> nexthop interface. Thus the dst could stay around until the route in
> the table the lookup was done is deleted which may be never.
>
> Address the problem by not forcing output device to be the l3mdev in
> the flow's output interface if the lookup didn't use the l3mdev. This
> then results in the dst using the right device according to the route.
>
> Changes in v2:
> - make the dev_out passed in by __ip_route_output_key_hash correct
> instead of checking the nh dev if FLOWI_FLAG_SKIP_NH_OIF is set as
> suggested by David.
>
> Fixes: 5f02ce24c2696 ("net: l3mdev: Allow the l3mdev to be a loopback")
> Reported-by: David Ahern <d...@cumulusnetworks.com>
> Suggested-by: David Ahern <d...@cumulusnetworks.com>
> Signed-off-by: Robert Shearman <rshea...@brocade.com>
> ---
> net/ipv4/route.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
> index acd69cfe2951..d9724889ff09 100644
> --- a/net/ipv4/route.c
> +++ b/net/ipv4/route.c
> @@ -2359,7 +2359,8 @@ struct rtable *__ip_route_output_key_hash(struct net
> *net, struct flowi4 *fl4,
> }
>
> /* L3 master device is the loopback for that domain */
> - dev_out = l3mdev_master_dev_rcu(dev_out) ? : net->loopback_dev;
> + dev_out = l3mdev_master_dev_rcu(FIB_RES_DEV(res)) ? :
> + net->loopback_dev;
> fl4->flowi4_oif = dev_out->ifindex;
> flags |= RTCF_LOCAL;
> goto make_route;
>
LGTM
Acked-by: David Ahern <d...@cumulusnetworks.com>
Tested-by: David Ahern <d...@cumulusnetworks.com>
