============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
kworker/1:4/6136 is trying to acquire lock:
ffff888104fa5158 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: sch_direct_xmit+0x153/0x4b0

but task is already holding lock:
ffff88810f104158 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __dev_queue_xmit+0x1676/0x3b50

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&qdisc_xmit_lock_key#4);
  lock(&qdisc_xmit_lock_key#4);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

11 locks held by kworker/1:4/6136:
 #0: ffff88810713dd48 ((wq_completion)mld){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc9000623fbc0 ((work_completion)(&(&idev->mc_ifc_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff88803eebe538 (&idev->mc_lock){+.+.}-{4:4}, at: mld_ifc_work+0x2d/0xd60
 #3: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: mld_sendpack+0x1e7/0xe60
 #4: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x126/0x550
 #5: ffffffff8e139f80 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27b/0x3b50
 #6: ffff88810f104158 (&qdisc_xmit_lock_key#4){+.-.}-{3:3}, at: __dev_queue_xmit+0x1676/0x3b50
 #7: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5b/0x450
 #8: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x452/0x1160
 #9: ffffffff8e139f80 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27b/0x3b50
 #10: ffff888119106258 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#3){+...}-{3:3}, at: __dev_queue_xmit+0x138a/0x3b50

stack backtrace:
CPU: 1 UID: 0 PID: 6136 Comm: kworker/1:4 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: mld mld_ifc_work
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_deadlock_bug+0x28b/0x2a0
 validate_chain+0x1a3f/0x2140
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 _raw_spin_lock+0x2e/0x40
 sch_direct_xmit+0x153/0x4b0
 __dev_queue_xmit+0x1857/0x3b50
 ip_finish_output2+0xd40/0x1160
 ip_output+0x29f/0x450
 iptunnel_xmit+0x5f8/0xa90
 ip_tunnel_xmit+0x1c41/0x2390
 ipgre_xmit+0x89e/0xc50
 dev_hard_start_xmit+0x2d7/0x830
 __dev_queue_xmit+0x1b8d/0x3b50
 ip6_finish_output2+0xfb3/0x1480
 ip6_output+0x340/0x550
 NF_HOOK+0x9e/0x380
 mld_sendpack+0x8d4/0xe60
 mld_ifc_work+0x83e/0xd60
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
