udp failures traced to e858fae2b0b8

udp failures traced to e858fae2b0b8

[David Ahern]

Mike:

UDP tests in my vrf unit test suite are failing. git bisect points to:


dsa@kenny:~/kernel-2.git$ git bisect good
e858fae2b0b8f41f0bed2cdffde25e7c97da38a7 is the first bad commit
commit e858fae2b0b8f41f0bed2cdffde25e7c97da38a7
Author: Mike Rapoport <rppt@linux.vnet.ibm.com>
Date:   Wed Jun 8 16:09:21 2016 +0300

     virtio_net: use common code for virtio_net_hdr and skb GSO conversion

     Replace open coded conversion between virtio_net_hdr to skb GSO 
info with
     virtio_net_hdr_{from,to}_skb

     Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
     Signed-off-by: David S. Miller <davem@davemloft.net>

:040000 040000 7e53f434e2d3a50ac685ce153dd92fc1a207de0e 
470864c731ae7dd680f9807d2a1a359c715a4270 M      drivers


On console I get the following:

[   80.414134] skbuff: bad partial csum: csum=34/6 len=40
[   80.416105] eth1: bad gso: type: 0, size: 0


Nothing special on the setup -- shell scripts and qemu commands that 
have worked fine for years. Host OS is debian/jessie:

dsa@kenny:dsa-ns:~$ /usr/bin/qemu-system-x86_64 --version
QEMU emulator version 2.1.2 (Debian 1:2.1+dfsg-12+deb8u6), Copyright (c) 
2003-2008 Fabrice Bellard

Networking arg:

-netdev 
type=tap,vhost=on,ifname=vm01-eth1,script=no,downscript=no,id=netdev1
-device virtio-net-pci,mac=02:e0:f9:1c:b9:74,netdev=netdev1,romfile=

tap device is connected to a bridge.

David

Re: udp failures traced to e858fae2b0b8

[Mike Rapoport]

Hi David,

On Sun, Jun 12, 2016 at 08:47:20PM -0600, David Ahern wrote:
> Mike:
> 
> UDP tests in my vrf unit test suite are failing. git bisect points to:

Are you testing host or guest kernel?
If it's the host, can you please check if the patch below helps? 
 
> dsa@kenny:~/kernel-2.git$ git bisect good
> e858fae2b0b8f41f0bed2cdffde25e7c97da38a7 is the first bad commit
> commit e858fae2b0b8f41f0bed2cdffde25e7c97da38a7
> Author: Mike Rapoport <rppt@linux.vnet.ibm.com>
> 
>     virtio_net: use common code for virtio_net_hdr and skb GSO conversion
> 
> On console I get the following:
> 
> [   80.414134] skbuff: bad partial csum: csum=34/6 len=40
> [   80.416105] eth1: bad gso: type: 0, size: 0
> 
> Networking arg:
> 
> -netdev
> type=tap,vhost=on,ifname=vm01-eth1,script=no,downscript=no,id=netdev1
> -device virtio-net-pci,mac=02:e0:f9:1c:b9:74,netdev=netdev1,romfile=
> 
> tap device is connected to a bridge.
> 
> David
> 

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 8cc6bf4..4884802 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1254,6 +1254,13 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 		return -EFAULT;
 	}
 
+	err = virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun));
+	if (err) {
+		this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
+		kfree_skb(skb);
+		return -EINVAL;
+	}
+
 	switch (tun->flags & TUN_TYPE_MASK) {
 	case IFF_TUN:
 		if (tun->flags & IFF_NO_PI) {
@@ -1280,13 +1287,6 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 		break;
 	}
 
-	err = virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun));
-	if (err) {
-		this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
-		kfree_skb(skb);
-		return -EINVAL;
-	}
-
 	/* copy skb_ubuf_info for callback when skb has no error */
 	if (zerocopy) {
 		skb_shinfo(skb)->destructor_arg = msg_control;

Re: udp failures traced to e858fae2b0b8

[David Ahern]

On 6/13/16 12:42 AM, Mike Rapoport wrote:
> Hi David,
>
> On Sun, Jun 12, 2016 at 08:47:20PM -0600, David Ahern wrote:
>> Mike:
>>
>> UDP tests in my vrf unit test suite are failing. git bisect points to:
>
> Are you testing host or guest kernel?

Problem is with guest. Guest is running net-next kernel.

host is running 4.6.

Re: udp failures traced to e858fae2b0b8

[Mike Rapoport]

On Mon, Jun 13, 2016 at 07:48:39AM -0600, David Ahern wrote:
> On 6/13/16 12:42 AM, Mike Rapoport wrote:
> >Hi David,
> >
> >On Sun, Jun 12, 2016 at 08:47:20PM -0600, David Ahern wrote:
> >>Mike:
> >>
> >>UDP tests in my vrf unit test suite are failing. git bisect points to:
> >
> >Are you testing host or guest kernel?
> 
> Problem is with guest. Guest is running net-next kernel.

Can you please check with the below patch?

> host is running 4.6.
> 

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 9af0a98..9f8be96 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -482,10 +482,6 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
 	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID)
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
 
-	skb->protocol = eth_type_trans(skb, dev);
-	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
-		 ntohs(skb->protocol), skb->len, skb->pkt_type);
-
 	if (virtio_net_hdr_to_skb(skb, &hdr->hdr,
 				  virtio_is_little_endian(vi->vdev))) {
 		net_warn_ratelimited("%s: bad gso: type: %u, size: %u\n",
@@ -494,6 +490,10 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
 		goto frame_err;
 	}
 
+	skb->protocol = eth_type_trans(skb, dev);
+	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
+		 ntohs(skb->protocol), skb->len, skb->pkt_type);
+
 	napi_gro_receive(&rq->napi, skb);
 	return;
 

Re: udp failures traced to e858fae2b0b8

[David Ahern]

On 6/13/16 12:40 PM, Mike Rapoport wrote:
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 9af0a98..9f8be96 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -482,10 +482,6 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
>  	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID)
>  		skb->ip_summed = CHECKSUM_UNNECESSARY;
>
> -	skb->protocol = eth_type_trans(skb, dev);
> -	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
> -		 ntohs(skb->protocol), skb->len, skb->pkt_type);
> -
>  	if (virtio_net_hdr_to_skb(skb, &hdr->hdr,
>  				  virtio_is_little_endian(vi->vdev))) {
>  		net_warn_ratelimited("%s: bad gso: type: %u, size: %u\n",
> @@ -494,6 +490,10 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
>  		goto frame_err;
>  	}
>
> +	skb->protocol = eth_type_trans(skb, dev);
> +	pr_debug("Receiving skb proto 0x%04x len %i type %i\n",
> +		 ntohs(skb->protocol), skb->len, skb->pkt_type);
> +
>  	napi_gro_receive(&rq->napi, skb);
>  	return;
>
>

Fixes the problem.