[PATCH v1] ip6_pol_route panic: Do not allow VLAN on loopback

[PATCH v1] ip6_pol_route panic: Do not allow VLAN on loopback

[Krishna Kumar]

I have tested two ways of fixing this panic:
	1. PATCH1: Do not allow vlan on lo.
	2. PATCH2: Do not propagate LOOPBACK to vlan devices.

Isn't it better to use PATCH1 and disallow vlan on lo?

The result of this patch is:

# modprobe 8021q
# vconfig add lo 43
ERROR: trying to add VLAN #43 to IF -:lo:-  error: Operation not supported

Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
---
 drivers/net/loopback.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff -ruNp org/drivers/net/loopback.c new1/drivers/net/loopback.c
--- org/drivers/net/loopback.c	2011-04-14 20:45:46.000000000 +0530
+++ new1/drivers/net/loopback.c	2011-04-14 20:47:09.000000000 +0530
@@ -173,7 +173,8 @@ static void loopback_setup(struct net_de
 		| NETIF_F_RXCSUM
 		| NETIF_F_HIGHDMA
 		| NETIF_F_LLTX
-		| NETIF_F_NETNS_LOCAL;
+		| NETIF_F_NETNS_LOCAL
+		| NETIF_F_VLAN_CHALLENGED;
 	dev->ethtool_ops	= &loopback_ethtool_ops;
 	dev->header_ops		= &eth_header_ops;
 	dev->netdev_ops		= &loopback_ops;

[PATCH v2] ip6_pol_route panic: Do not propagate LOOPBACK to VLAN

[Krishna Kumar]

I have tested two ways of fixing this panic:
	1. PATCH1: Do not allow vlan on lo.
	2. PATCH2: Do not propagate LOOPBACK to vlan devices.

Isn't it better to use PATCH1 and disallow vlan on lo?

The result of this patch is:

# modprobe 8021q
# vconfig add lo 43
# ifconfig lo.69 hw ether 00:80:48:BA:d1:30
# ping6 -c 3 fe80::280:48ff:feba:d130
connect: Cannot assign requested address
(no panic)

Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
---
 net/8021q/vlan_dev.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff -ruNp org/net/8021q/vlan_dev.c new2/net/8021q/vlan_dev.c
--- org/net/8021q/vlan_dev.c	2011-04-14 20:42:56.000000000 +0530
+++ new2/net/8021q/vlan_dev.c	2011-04-14 20:44:35.000000000 +0530
@@ -525,7 +525,8 @@ static int vlan_dev_init(struct net_devi
 
 	/* IFF_BROADCAST|IFF_MULTICAST; ??? */
 	dev->flags  = real_dev->flags & ~(IFF_UP | IFF_PROMISC | IFF_ALLMULTI |
-					  IFF_MASTER | IFF_SLAVE);
+					  IFF_MASTER | IFF_SLAVE |
+					  IFF_LOOPBACK);
 	dev->iflink = real_dev->ifindex;
 	dev->state  = (real_dev->state & ((1<<__LINK_STATE_NOCARRIER) |
 					  (1<<__LINK_STATE_DORMANT))) |

Re: [PATCH v1] ip6_pol_route panic: Do not allow VLAN on loopback

[David Miller]

From: Krishna Kumar <krkumar2@in.ibm.com>
Date: Thu, 14 Apr 2011 21:37:04 +0530

> I have tested two ways of fixing this panic:
> 	1. PATCH1: Do not allow vlan on lo.
> 	2. PATCH2: Do not propagate LOOPBACK to vlan devices.
> 
> Isn't it better to use PATCH1 and disallow vlan on lo?
> 
> The result of this patch is:
> 
> # modprobe 8021q
> # vconfig add lo 43
> ERROR: trying to add VLAN #43 to IF -:lo:-  error: Operation not supported
> 
> Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>

I applied this patch #1, and added some commentary to the commit message
to explain the ipv6 crash issue this fixes.

Thanks.