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Subject[PATCH 3.12 74/86] ip6mr: fix notification device destruction
Date
From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

[ Upstream commit 723b929ca0f79c0796f160c2eeda4597ee98d2b8 ]

Andrey Konovalov reported a BUG caused by the ip6mr code which is caused
because we call unregister_netdevice_many for a device that is already
being destroyed. In IPv4's ipmr that has been resolved by two commits
long time ago by introducing the "notify" parameter to the delete
function and avoiding the unregister when called from a notifier, so
let's do the same for ip6mr.

The trace from Andrey:
------------[ cut here ]------------
kernel BUG at net/core/dev.c:6813!
invalid opcode: 0000 [#1] SMP KASAN
Modules linked in:
CPU: 1 PID: 1165 Comm: kworker/u4:3 Not tainted 4.11.0-rc7+ #251
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs
01/01/2011
Workqueue: netns cleanup_net
task: ffff880069208000 task.stack: ffff8800692d8000
RIP: 0010:rollback_registered_many+0x348/0xeb0 net/core/dev.c:6813
RSP: 0018:ffff8800692de7f0 EFLAGS: 00010297
RAX: ffff880069208000 RBX: 0000000000000002 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88006af90569
RBP: ffff8800692de9f0 R08: ffff8800692dec60 R09: 0000000000000000
R10: 0000000000000006 R11: 0000000000000000 R12: ffff88006af90070
R13: ffff8800692debf0 R14: dffffc0000000000 R15: ffff88006af90000
FS: 0000000000000000(0000) GS:ffff88006cb00000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe7e897d870 CR3: 00000000657e7000 CR4: 00000000000006e0
Call Trace:
unregister_netdevice_many.part.105+0x87/0x440 net/core/dev.c:7881
unregister_netdevice_many+0xc8/0x120 net/core/dev.c:7880
ip6mr_device_event+0x362/0x3f0 net/ipv6/ip6mr.c:1346
notifier_call_chain+0x145/0x2f0 kernel/notifier.c:93
__raw_notifier_call_chain kernel/notifier.c:394
raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
call_netdevice_notifiers_info+0x51/0x90 net/core/dev.c:1647
call_netdevice_notifiers net/core/dev.c:1663
rollback_registered_many+0x919/0xeb0 net/core/dev.c:6841
unregister_netdevice_many.part.105+0x87/0x440 net/core/dev.c:7881
unregister_netdevice_many net/core/dev.c:7880
default_device_exit_batch+0x4fa/0x640 net/core/dev.c:8333
ops_exit_list.isra.4+0x100/0x150 net/core/net_namespace.c:144
cleanup_net+0x5a8/0xb40 net/core/net_namespace.c:463
process_one_work+0xc04/0x1c10 kernel/workqueue.c:2097
worker_thread+0x223/0x19c0 kernel/workqueue.c:2231
kthread+0x35e/0x430 kernel/kthread.c:231
ret_from_fork+0x31/0x40 arch/x86/entry/entry_64.S:430
Code: 3c 32 00 0f 85 70 0b 00 00 48 b8 00 02 00 00 00 00 ad de 49 89
47 78 e9 93 fe ff ff 49 8d 57 70 49 8d 5f 78 eb 9e e8 88 7a 14 fe <0f>
0b 48 8b 9d 28 fe ff ff e8 7a 7a 14 fe 48 b8 00 00 00 00 00
RIP: rollback_registered_many+0x348/0xeb0 RSP: ffff8800692de7f0
---[ end trace e0b29c57e9b3292c ]---

Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv6/ip6mr.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 56aa540d77f6..2dcb19cb8f61 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -776,7 +776,8 @@ failure:
* Delete a VIF entry
*/

-static int mif6_delete(struct mr6_table *mrt, int vifi, struct list_head *head)
+static int mif6_delete(struct mr6_table *mrt, int vifi, int notify,
+ struct list_head *head)
{
struct mif_device *v;
struct net_device *dev;
@@ -822,7 +823,7 @@ static int mif6_delete(struct mr6_table *mrt, int vifi, struct list_head *head)
dev->ifindex, &in6_dev->cnf);
}

- if (v->flags & MIFF_REGISTER)
+ if ((v->flags & MIFF_REGISTER) && !notify)
unregister_netdevice_queue(dev, head);

dev_put(dev);
@@ -1332,7 +1333,6 @@ static int ip6mr_device_event(struct notifier_block *this,
struct mr6_table *mrt;
struct mif_device *v;
int ct;
- LIST_HEAD(list);

if (event != NETDEV_UNREGISTER)
return NOTIFY_DONE;
@@ -1341,10 +1341,9 @@ static int ip6mr_device_event(struct notifier_block *this,
v = &mrt->vif6_table[0];
for (ct = 0; ct < mrt->maxvif; ct++, v++) {
if (v->dev == dev)
- mif6_delete(mrt, ct, &list);
+ mif6_delete(mrt, ct, 1, NULL);
}
}
- unregister_netdevice_many(&list);

return NOTIFY_DONE;
}
@@ -1549,7 +1548,7 @@ static void mroute_clean_tables(struct mr6_table *mrt, bool all)
for (i = 0; i < mrt->maxvif; i++) {
if (!all && (mrt->vif6_table[i].flags & VIFF_STATIC))
continue;
- mif6_delete(mrt, i, &list);
+ mif6_delete(mrt, i, 0, &list);
}
unregister_netdevice_many(&list);

@@ -1702,7 +1701,7 @@ int ip6_mroute_setsockopt(struct sock *sk, int optname, char __user *optval, uns
if (copy_from_user(&mifi, optval, sizeof(mifi_t)))
return -EFAULT;
rtnl_lock();
- ret = mif6_delete(mrt, mifi, NULL);
+ ret = mif6_delete(mrt, mifi, 0, NULL);
rtnl_unlock();
return ret;

--
2.12.2
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