Re: [PATCH net] mpls: handle device renames for per-device sysctls

2015-06-11 Thread David Miller
From: Robert Shearman 
Date: Thu, 11 Jun 2015 19:58:26 +0100

> If a device is renamed and the original name is subsequently reused
> for a new device, the following warning is generated:
 ...
> Fix this by unregistering the previous sysctl table (registered for
> the path containing the original device name) and re-registering the
> table for the path containing the new device name.
> 
> Fixes: 37bde79979c3 ("mpls: Per-device enabling of packet input")
> Reported-by: Scott Feldman 
> Signed-off-by: Robert Shearman 

Applied, thanks Robert.
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[PATCH net] mpls: handle device renames for per-device sysctls

2015-06-11 Thread Robert Shearman
If a device is renamed and the original name is subsequently reused
for a new device, the following warning is generated:

sysctl duplicate entry: /net/mpls/conf/veth0//input
CPU: 3 PID: 1379 Comm: ip Not tainted 4.1.0-rc4+ #20
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 
1.7.5-20140531_083030-gandalf 04/01/2014
   81566aaf 
 81236279 88002f7d7f00  88000db336d8
 88000db33698 0005 88002e046000 8800168c9280
Call Trace:
 [] ? dump_stack+0x40/0x50
 [] ? __register_sysctl_table+0x289/0x5a0
 [] ? mpls_dev_notify+0x1ff/0x300 [mpls_router]
 [] ? notifier_call_chain+0x4f/0x70
 [] ? register_netdevice+0x2b2/0x480
 [] ? veth_newlink+0x178/0x2d3 [veth]
 [] ? rtnl_newlink+0x73c/0x8e0
 [] ? rtnl_newlink+0x16a/0x8e0
 [] ? __kmalloc_reserve.isra.30+0x32/0x90
 [] ? rtnetlink_rcv_msg+0x8d/0x250
 [] ? __alloc_skb+0x47/0x1f0
 [] ? __netlink_lookup+0xab/0xe0
 [] ? rtnetlink_rcv+0x30/0x30
 [] ? netlink_rcv_skb+0xb0/0xd0
 [] ? rtnetlink_rcv+0x24/0x30
 [] ? netlink_unicast+0x107/0x1a0
 [] ? netlink_sendmsg+0x50e/0x630
 [] ? sock_sendmsg+0x3c/0x50
 [] ? ___sys_sendmsg+0x27b/0x290
 [] ? mem_cgroup_try_charge+0x88/0x110
 [] ? mem_cgroup_commit_charge+0x56/0xa0
 [] ? do_filp_open+0x30/0xa0
 [] ? __sys_sendmsg+0x3e/0x80
 [] ? system_call_fastpath+0x16/0x75

Fix this by unregistering the previous sysctl table (registered for
the path containing the original device name) and re-registering the
table for the path containing the new device name.

Fixes: 37bde79979c3 ("mpls: Per-device enabling of packet input")
Reported-by: Scott Feldman 
Signed-off-by: Robert Shearman 
---
 net/mpls/af_mpls.c | 11 +++
 1 file changed, 11 insertions(+)

diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index bff427f31924..1f93a5978f2a 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -564,6 +564,17 @@ static int mpls_dev_notify(struct notifier_block *this, 
unsigned long event,
case NETDEV_UNREGISTER:
mpls_ifdown(dev);
break;
+   case NETDEV_CHANGENAME:
+   mdev = mpls_dev_get(dev);
+   if (mdev) {
+   int err;
+
+   mpls_dev_sysctl_unregister(mdev);
+   err = mpls_dev_sysctl_register(dev, mdev);
+   if (err)
+   return notifier_from_errno(err);
+   }
+   break;
}
return NOTIFY_OK;
 }
-- 
2.1.4

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