[3.13.y.z extended stable] Patch "vlan: free percpu stats in device destructor" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    vlan: free percpu stats in device destructor

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 7d41a5bd6db948a679fe97210fba55a936c45a0c Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet at google.com>
Date: Wed, 2 Jul 2014 02:25:15 -0700
Subject: vlan: free percpu stats in device destructor

[ Upstream commit a48e5fafecfb9c0c807d7e7284b5ff884dfb7a3a ]

Madalin-Cristian reported crashs happening after a recent commit
(5a4ae5f6e7d4 "vlan: unnecessary to check if vlan_pcpu_stats is NULL")

-----------------------------------------------------------------------
root at p5040ds:~# vconfig add eth8 1
root at p5040ds:~# vconfig rem eth8.1
Unable to handle kernel paging request for data at address 0x2bc88028
Faulting instruction address: 0xc058e950
Oops: Kernel access of bad area, sig: 11 [#1]
SMP NR_CPUS=8 CoreNet Generic
Modules linked in:
CPU: 3 PID: 2167 Comm: vconfig Tainted: G        W     3.16.0-rc3-00346-g65e85bf #2
task: e7264d90 ti: e2c2c000 task.ti: e2c2c000
NIP: c058e950 LR: c058ea30 CTR: c058e900
REGS: e2c2db20 TRAP: 0300   Tainted: G        W      (3.16.0-rc3-00346-g65e85bf)
MSR: 00029002 <CE,EE,ME>  CR: 48000428  XER: 20000000
DEAR: 2bc88028 ESR: 00000000
GPR00: c047299c e2c2dbd0 e7264d90 00000000 2bc88000 00000000 ffffffff 00000000
GPR08: 0000000f 00000000 000000ff 00000000 28000422 10121928 10100000 10100000
GPR16: 10100000 00000000 c07c5968 00000000 00000000 00000000 e2c2dc48 e7838000
GPR24: c07c5bac c07c58a8 e77290cc c07b0000 00000000 c05de6c0 e7838000 e2c2dc48
NIP [c058e950] vlan_dev_get_stats64+0x50/0x170
LR [c058ea30] vlan_dev_get_stats64+0x130/0x170
Call Trace:
[e2c2dbd0] [ffffffea] 0xffffffea (unreliable)
[e2c2dc20] [c047299c] dev_get_stats+0x4c/0x140
[e2c2dc40] [c0488ca8] rtnl_fill_ifinfo+0x3d8/0x960
[e2c2dd70] [c0489f4c] rtmsg_ifinfo+0x6c/0x110
[e2c2dd90] [c04731d4] rollback_registered_many+0x344/0x3b0
[e2c2ddd0] [c047332c] rollback_registered+0x2c/0x50
[e2c2ddf0] [c0476058] unregister_netdevice_queue+0x78/0xf0
[e2c2de00] [c058d800] unregister_vlan_dev+0xc0/0x160
[e2c2de20] [c058e360] vlan_ioctl_handler+0x1c0/0x550
[e2c2de90] [c045d11c] sock_ioctl+0x28c/0x2f0
[e2c2deb0] [c010d070] do_vfs_ioctl+0x90/0x7b0
[e2c2df20] [c010d7d0] SyS_ioctl+0x40/0x80
[e2c2df40] [c000f924] ret_from_syscall+0x0/0x3c

Fix this problem by freeing percpu stats from dev->destructor() instead
of ndo_uninit()

Reported-by: Madalin-Cristian Bucur <madalin.bucur at freescale.com>
Signed-off-by: Eric Dumazet <edumazet at google.com>
Tested-by: Madalin-Cristian Bucur <madalin.bucur at freescale.com>
Fixes: 5a4ae5f6e7d4 ("vlan: unnecessary to check if vlan_pcpu_stats is NULL")
Cc: Li RongQing <roy.qing.li at gmail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/8021q/vlan_dev.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/net/8021q/vlan_dev.c b/net/8021q/vlan_dev.c
index 731ede4..df13d18 100644
--- a/net/8021q/vlan_dev.c
+++ b/net/8021q/vlan_dev.c
@@ -632,8 +632,6 @@ static void vlan_dev_uninit(struct net_device *dev)
 	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
 	int i;

-	free_percpu(vlan->vlan_pcpu_stats);
-	vlan->vlan_pcpu_stats = NULL;
 	for (i = 0; i < ARRAY_SIZE(vlan->egress_priority_map); i++) {
 		while ((pm = vlan->egress_priority_map[i]) != NULL) {
 			vlan->egress_priority_map[i] = pm->next;
@@ -793,6 +791,15 @@ static const struct net_device_ops vlan_netdev_ops = {
 	.ndo_get_lock_subclass  = vlan_dev_get_lock_subclass,
 };

+static void vlan_dev_free(struct net_device *dev)
+{
+	struct vlan_dev_priv *vlan = vlan_dev_priv(dev);
+
+	free_percpu(vlan->vlan_pcpu_stats);
+	vlan->vlan_pcpu_stats = NULL;
+	free_netdev(dev);
+}
+
 void vlan_setup(struct net_device *dev)
 {
 	ether_setup(dev);
@@ -802,7 +809,7 @@ void vlan_setup(struct net_device *dev)
 	dev->tx_queue_len	= 0;

 	dev->netdev_ops		= &vlan_netdev_ops;
-	dev->destructor		= free_netdev;
+	dev->destructor		= vlan_dev_free;
 	dev->ethtool_ops	= &vlan_ethtool_ops;

 	memset(dev->broadcast, 0, ETH_ALEN);
--
1.9.1