3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gao Feng <gfree.wind@xxxxxxxxxxx> [ Upstream commit 9745e362add89432d2c951272a99b0a5fe4348a9 ] The register_vlan_device would invoke free_netdev directly, when register_vlan_dev failed. It would trigger the BUG_ON in free_netdev if the dev was already registered. In this case, the netdev would be freed in netdev_run_todo later. So add one condition check now. Only when dev is not registered, then free it directly. The following is the part coredump when netdev_upper_dev_link failed in register_vlan_dev. I removed the lines which are too long. [ 411.237457] ------------[ cut here ]------------ [ 411.237458] kernel BUG at net/core/dev.c:7998! [ 411.237484] invalid opcode: 0000 [#1] SMP [ 411.237705] [last unloaded: 8021q] [ 411.237718] CPU: 1 PID: 12845 Comm: vconfig Tainted: G E 4.12.0-rc5+ #6 [ 411.237737] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/02/2015 [ 411.237764] task: ffff9cbeb6685580 task.stack: ffffa7d2807d8000 [ 411.237782] RIP: 0010:free_netdev+0x116/0x120 [ 411.237794] RSP: 0018:ffffa7d2807dbdb0 EFLAGS: 00010297 [ 411.237808] RAX: 0000000000000002 RBX: ffff9cbeb6ba8fd8 RCX: 0000000000001878 [ 411.237826] RDX: 0000000000000001 RSI: 0000000000000282 RDI: 0000000000000000 [ 411.237844] RBP: ffffa7d2807dbdc8 R08: 0002986100029841 R09: 0002982100029801 [ 411.237861] R10: 0004000100029980 R11: 0004000100029980 R12: ffff9cbeb6ba9000 [ 411.238761] R13: ffff9cbeb6ba9060 R14: ffff9cbe60f1a000 R15: ffff9cbeb6ba9000 [ 411.239518] FS: 00007fb690d81700(0000) GS:ffff9cbebb640000(0000) knlGS:0000000000000000 [ 411.239949] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 411.240454] CR2: 00007f7115624000 CR3: 0000000077cdf000 CR4: 00000000003406e0 [ 411.240936] Call Trace: [ 411.241462] vlan_ioctl_handler+0x3f1/0x400 [8021q] [ 411.241910] sock_ioctl+0x18b/0x2c0 [ 411.242394] do_vfs_ioctl+0xa1/0x5d0 [ 411.242853] ? sock_alloc_file+0xa6/0x130 [ 411.243465] SyS_ioctl+0x79/0x90 [ 411.243900] entry_SYSCALL_64_fastpath+0x1e/0xa9 [ 411.244425] RIP: 0033:0x7fb69089a357 [ 411.244863] RSP: 002b:00007ffcd04e0fc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [ 411.245445] RAX: ffffffffffffffda RBX: 00007ffcd04e2884 RCX: 00007fb69089a357 [ 411.245903] RDX: 00007ffcd04e0fd0 RSI: 0000000000008983 RDI: 0000000000000003 [ 411.246527] RBP: 00007ffcd04e0fd0 R08: 0000000000000000 R09: 1999999999999999 [ 411.246976] R10: 000000000000053f R11: 0000000000000202 R12: 0000000000000004 [ 411.247414] R13: 00007ffcd04e1128 R14: 00007ffcd04e2888 R15: 0000000000000001 [ 411.249129] RIP: free_netdev+0x116/0x120 RSP: ffffa7d2807dbdb0 Signed-off-by: Gao Feng <gfree.wind@xxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/8021q/vlan.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/8021q/vlan.c +++ b/net/8021q/vlan.c @@ -278,7 +278,8 @@ static int register_vlan_device(struct n return 0; out_free_newdev: - free_netdev(new_dev); + if (new_dev->reg_state == NETREG_UNINITIALIZED) + free_netdev(new_dev); return err; }