Bug 13348

Summary: [PATCH]Unable to clone tagged VLAN interface for use with macvlan driver
Product: Networking Reporter: sg.tweak
Component: IPV4Assignee: Stephen Hemminger (stephen)
Status: CLOSED CODE_FIX    
Severity: normal CC: akpm, alan, rjw, sg.tweak
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 2.6.29.3 Subsystem:
Regression: No Bisected commit-id:
Attachments: macvlan driver patch fixes invalid header length

Description sg.tweak 2009-05-20 00:52:15 UTC 
It is not possible to make clone of tagged VLAN interface to be used as
mac-based vlan interfave.

How reproducible:
Use any 802.1q tagged vlan interface, e.g. eth2.700 and clone it:

  ip link add link eth2.700 address 00:04:75:cb:38:09 macvlan0 type macvlan
  ip link set dev macvlan0 up
  ip addr add 10.195.1.1/24 dev macvlan0

So far, so good. Now try to ping anything via macvlan0:

  ping 10.195.1.2


Actual results:
For every attempted packet tx kernel writes to console:

------------[ cut here ]------------
WARNING: at net/8021q/vlan_dev.c:254 vlan_dev_hard_header+0x36/0x126 [8021q]()
Hardware name: M22ES
Modules linked in: arptable_filter arp_tables bridge veth macvlan arc4 ecb ppp_mppe ppp_async crc_ccitt ppp_generic slhc autofs4 sunrpc 8021q garp stp ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 xt_state nf_conntrack xt_tcpudp x_tables dm_mirror dm_region_hash dm_log dm_multipath dm_mod sbs sbshc lp floppy snd_intel8x0 joydev snd_seq_dummy snd_intel8x0m snd_ac97_codec ide_cd_mod ac97_bus snd_seq_oss cdrom snd_seq_midi_event serio_raw snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss parport_pc snd_pcm parport battery 8139cp snd_timer i2c_sis96x ac button snd rtc_cmos rtc_core 8139too soundcore rtc_lib mii i2c_core pcspkr snd_page_alloc pata_sis libata sd_mod scsi_mod ext3 jbd ehci_hcd ohci_hcd uhci_hcd [last unloaded: ip_tables]
Pid: 0, comm: swapper Tainted: G        W  2.6.29.3 #1
Call Trace:
 [<c0425f48>] warn_slowpath+0x60/0x9f
 [<c0425f6f>] warn_slowpath+0x87/0x9f
 [<dffb850d>] vlan_dev_hard_header+0x0/0x126 [8021q]
 [<dffb8543>] vlan_dev_hard_header+0x36/0x126 [8021q]
 [<dffb850d>] vlan_dev_hard_header+0x0/0x126 [8021q]
 [<df83155d>] macvlan_hard_header+0x3c/0x47 [macvlan]
 [<df831521>] macvlan_hard_header+0x0/0x47 [macvlan]
 [<c062bf3f>] arp_create+0xef/0x1ff
 [<c062c08c>] arp_send+0x3d/0x54
 [<c062c916>] arp_solicit+0x16c/0x177
 [<c05fadd2>] neigh_timer_handler+0x227/0x269
 [<c05fabab>] neigh_timer_handler+0x0/0x269
 [<c042ce4d>] run_timer_softirq+0xf0/0x141
 [<c0429e5a>] __do_softirq+0x76/0xf8
 [<c0429de4>] __do_softirq+0x0/0xf8
 <IRQ>  [<c044fb67>] handle_level_irq+0x0/0xad
 [<c0429db7>] irq_exit+0x35/0x62
 [<c04046bb>] do_IRQ+0xdf/0xf4
 [<c04035a7>] common_interrupt+0x27/0x2c
 [<c04079c5>] default_idle+0x2a/0x3d
 [<c0401bb6>] cpu_idle+0x57/0x70
---[ end trace 2def39ad9ce2acf6 ]---
Comment 1 sg.tweak 2009-05-20 15:31:01 UTC 
Problem solved. Macvlan driver is always use standard ethernet header length for all types of interface to which it is linked.
This patch fixes this problem (tested on 2.6.29.3 and 2.6.29.4 kernels):

--- a/drivers/net/macvlan.c	2009-05-09 01:47:21.000000000 +0300
+++ b/drivers/net/macvlan.c	2009-05-20 17:40:29.000000000 +0300
@@ -311,6 +311,7 @@
 				  (lowerdev->state & MACVLAN_STATE_MASK);
 	dev->features 		= lowerdev->features & MACVLAN_FEATURES;
 	dev->iflink		= lowerdev->ifindex;
+	dev->hard_header_len 	= lowerdev->hard_header_len;
 
 	macvlan_set_lockdep_class(dev);
Comment 2 sg.tweak 2009-05-20 15:32:28 UTC 
Created attachment 21456 [details]
macvlan driver patch fixes invalid header length
Comment 3 Alan 2009-05-21 16:25:28 UTC 
Please send a copy of the patch and a Signed-off-by: line (see Documentation/SubmittingPatches) to
netdev@vger.kernel.org for Dave Miller to pick up.
Comment 4 Alan 2009-05-25 22:31:49 UTC 
Patch is not yet merged
Comment 5 Rafael J. Wysocki 2009-05-25 22:41:31 UTC 
(In reply to comment #4)
> Patch is not yet merged

Yes, and that's why I didn't close the bug.
Comment 6 Andrew Morton 2009-05-27 07:10:58 UTC 
There's no sign of the reporter on netdev - reporters will often disappear.

I rescued the fix - thanks.