[3.8.y.z extended stable] Patch "virtio: delete napi structures from netdev before releasing memory" has been added to staging queue

[Kamal Mostafa]

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

    virtio: delete napi structures from netdev before releasing memory

to the linux-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.16.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From cbc0084b42769e378a88c7ba6bbd1310af60118b Mon Sep 17 00:00:00 2001
From: Andrey Vagin <avagin at openvz.org>
Date: Thu, 5 Dec 2013 18:36:21 +0400
Subject: virtio: delete napi structures from netdev before releasing memory

[ Upstream commit d4fb84eefe5164f6a6ea51d0a9e26280c661a0dd ]

free_netdev calls netif_napi_del too, but it's too late, because napi
structures are placed on vi->rq. netif_napi_add() is called from
virtnet_alloc_queues.

general protection fault: 0000 [#1] SMP
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in: ip6table_filter ip6_tables iptable_filter ip_tables virtio_balloon pcspkr virtio_net(-) i2c_pii
CPU: 1 PID: 347 Comm: rmmod Not tainted 3.13.0-rc2+ #171
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
task: ffff8800b779c420 ti: ffff8800379e0000 task.ti: ffff8800379e0000
RIP: 0010:[<ffffffff81322e19>]  [<ffffffff81322e19>] __list_del_entry+0x29/0xd0
RSP: 0018:ffff8800379e1dd0  EFLAGS: 00010a83
RAX: 6b6b6b6b6b6b6b6b RBX: ffff8800379c2fd0 RCX: dead000000200200
RDX: 6b6b6b6b6b6b6b6b RSI: 0000000000000001 RDI: ffff8800379c2fd0
RBP: ffff8800379e1dd0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: ffff8800379c2f90
R13: ffff880037839160 R14: 0000000000000000 R15: 00000000013352f0
FS:  00007f1400e34740(0000) GS:ffff8800bfb00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007f464124c763 CR3: 00000000b68cf000 CR4: 00000000000006e0
Stack:
 ffff8800379e1df0 ffffffff8155beab 6b6b6b6b6b6b6b2b ffff8800378391c0
 ffff8800379e1e18 ffffffff8156499b ffff880037839be0 ffff880037839d20
 ffff88003779d3f0 ffff8800379e1e38 ffffffffa003477c ffff88003779d388
Call Trace:
 [<ffffffff8155beab>] netif_napi_del+0x1b/0x80
 [<ffffffff8156499b>] free_netdev+0x8b/0x110
 [<ffffffffa003477c>] virtnet_remove+0x7c/0x90 [virtio_net]
 [<ffffffff813ae323>] virtio_dev_remove+0x23/0x80
 [<ffffffff813f62ef>] __device_release_driver+0x7f/0xf0
 [<ffffffff813f6ca0>] driver_detach+0xc0/0xd0
 [<ffffffff813f5f28>] bus_remove_driver+0x58/0xd0
 [<ffffffff813f72ec>] driver_unregister+0x2c/0x50
 [<ffffffff813ae65e>] unregister_virtio_driver+0xe/0x10
 [<ffffffffa0036942>] virtio_net_driver_exit+0x10/0x6ce [virtio_net]
 [<ffffffff810d7cf2>] SyS_delete_module+0x172/0x220
 [<ffffffff810a732d>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff810f5d4c>] ? __audit_syscall_entry+0x9c/0xf0
 [<ffffffff81677f69>] system_call_fastpath+0x16/0x1b
Code: 00 00 55 48 8b 17 48 b9 00 01 10 00 00 00 ad de 48 8b 47 08 48 89 e5 48 39 ca 74 29 48 b9 00 02 20 00 00 00
RIP  [<ffffffff81322e19>] __list_del_entry+0x29/0xd0
 RSP <ffff8800379e1dd0>
---[ end trace d5931cd3f87c9763 ]---

Fixes: 986a4f4d452d (virtio_net: multiqueue support)
Cc: Rusty Russell <rusty at rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst at redhat.com>
Signed-off-by: Andrey Vagin <avagin at openvz.org>
Acked-by: Michael S. Tsirkin <mst at redhat.com>
Acked-by: Jason Wang <jasowang at redhat.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/virtio_net.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c3bcb4a..fa2385a 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1265,6 +1265,11 @@ static void virtnet_config_changed(struct virtio_device *vdev)

 static void virtnet_free_queues(struct virtnet_info *vi)
 {
+	int i;
+
+	for (i = 0; i < vi->max_queue_pairs; i++)
+		netif_napi_del(&vi->rq[i].napi);
+
 	kfree(vi->rq);
 	kfree(vi->sq);
 }
--
1.8.3.2