This is a note to let you know that I've just added the patch titled ip6mr: fix notification device destruction to the 4.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ip6mr-fix-notification-device-destruction.patch and it can be found in the queue-4.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Sat Apr 29 08:22:40 CEST 2017 From: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx> Date: Fri, 21 Apr 2017 20:42:16 +0300 Subject: ip6mr: fix notification device destruction From: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx> [ 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@xxxxxxxxxx> Signed-off-by: Nikolay Aleksandrov <nikolay@xxxxxxxxxxxxxxxxxxx> Tested-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv6/ip6mr.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -774,7 +774,8 @@ 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; @@ -820,7 +821,7 @@ static int mif6_delete(struct mr6_table dev->ifindex, &in6_dev->cnf); } - if (v->flags & MIFF_REGISTER) + if ((v->flags & MIFF_REGISTER) && !notify) unregister_netdevice_queue(dev, head); dev_put(dev); @@ -1331,7 +1332,6 @@ static int ip6mr_device_event(struct not struct mr6_table *mrt; struct mif_device *v; int ct; - LIST_HEAD(list); if (event != NETDEV_UNREGISTER) return NOTIFY_DONE; @@ -1340,10 +1340,9 @@ static int ip6mr_device_event(struct not 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; } @@ -1552,7 +1551,7 @@ static void mroute_clean_tables(struct m 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); @@ -1706,7 +1705,7 @@ int ip6_mroute_setsockopt(struct sock *s 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; Patches currently in stable-queue which might be from nikolay@xxxxxxxxxxxxxxxxxxx are queue-4.10/ip6mr-fix-notification-device-destruction.patch