============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
syz.2.3785/20067 is trying to acquire lock:
ffff88817524a958 (&qdisc_xmit_lock_key#5){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0

but task is already holding lock:
ffff8881a6c95958 (&qdisc_xmit_lock_key#5){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0

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

       CPU0
       ----
  lock(&qdisc_xmit_lock_key#5);
  lock(&qdisc_xmit_lock_key#5);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

16 locks held by syz.2.3785/20067:
 #0: ffff888024c97180 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x16c/0xb30
 #1: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: ___pte_offset_map+0x29/0x240
 #2: ffff8881165c6e58 (ptlock_ptr(ptdesc)#2){+.+.}-{3:3}, at: __pte_offset_map_lock+0x13d/0x210
 #3: ffffc90000a08ce0 ((&n->timer)){+.-.}-{0:0}, at: call_timer_fn+0xd4/0x5a0
 #4: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: ndisc_send_skb+0x1fd/0x14e0
 #5: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x126/0x550
 #6: ffffffff8e35a3c0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2a7/0x32b0
 #7: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: bond_start_xmit+0xc9/0x1960
 #8: ffffffff8e35a3c0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2a7/0x32b0
 #9: ffff888190df2228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0xf23/0x32b0
 #10: ffff8881a6c95958 (&qdisc_xmit_lock_key#5){+.-.}-{3:3}, at: sch_direct_xmit+0x15f/0x4c0
 #11: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: ip_output+0x5b/0x450
 #12: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0x3d0/0xff0
 #13: ffffffff8e35a360 (rcu_read_lock){....}-{1:3}, at: arp_xmit+0x23/0x270
 #14: ffffffff8e35a3c0 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x2a7/0x32b0
 #15: ffff88811e938228 (dev->qdisc_tx_busylock ?: &qdisc_tx_busylock#5){+...}-{3:3}, at: __dev_queue_xmit+0xf23/0x32b0

stack backtrace:
CPU: 1 UID: 0 PID: 20067 Comm: syz.2.3785 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
Call Trace:
 <IRQ>
 dump_stack_lvl+0xe8/0x150
 print_deadlock_bug+0x279/0x290
 __lock_acquire+0x253f/0x2cf0
 lock_acquire+0x106/0x330
 _raw_spin_lock+0x2e/0x40
 sch_direct_xmit+0x15f/0x4c0
 __dev_queue_xmit+0x13c4/0x32b0
 NF_HOOK+0x33a/0x3c0
 arp_xmit+0x16c/0x270
 arp_solicit+0xbe0/0xe40
 __neigh_event_send+0xf05/0x14a0
 neigh_resolve_output+0x198/0x750
 ip_finish_output2+0xbb6/0xff0
 ip_output+0x29f/0x450
 iptunnel_xmit+0x59f/0xa00
 ip_tunnel_xmit+0x1cea/0x2430
 __gre_xmit+0x19e/0x240
 erspan_xmit+0xa87/0x1440
 dev_hard_start_xmit+0x2cd/0x7f0
 sch_direct_xmit+0x251/0x4c0
 __dev_queue_xmit+0x13c4/0x32b0
 bond_start_xmit+0x77d/0x1960
 dev_hard_start_xmit+0x2cd/0x7f0
 __dev_queue_xmit+0x14ed/0x32b0
 ip6_output+0x340/0x550
 ndisc_send_skb+0xbaa/0x14e0
 ndisc_solicit+0x374/0x670
 neigh_timer_handler+0xb50/0x1190
 call_timer_fn+0x192/0x5a0
 __run_timer_base+0x652/0x8b0
 run_timer_softirq+0xb7/0x170
 handle_softirqs+0x22a/0x7c0
 __irq_exit_rcu+0x5f/0x150
 irq_exit_rcu+0x9/0x30
 sysvec_apic_timer_interrupt+0xa6/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:__kasan_check_read+0x0/0x20
Code: d3 8d 48 89 de e8 c0 26 fe fe 31 ed eb cf cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 89 f6 48 8b 0c 24 31 d2 e9 8f e5 ff ff 66 66 66 66 66
RSP: 0018:ffffc900042c7678 EFLAGS: 00000286
RAX: ffffffff820e9083 RBX: 0000000000000000 RCX: ffff88810bbd8000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffea0006b14530
RBP: ffffc900042c7930 R08: ffffea0006b14507 R09: 1ffffd4000d628a0
R10: dffffc0000000000 R11: fffff94000d628a1 R12: 00007f26e9f0d000
R13: dffffc0000000000 R14: ffff88811efda868 R15: ffffea0006b14530
 unmap_page_range+0x1a4e/0x4160
 unmap_vmas+0x3c0/0x5c0
 exit_mmap+0x251/0xb30
 __mmput+0x118/0x430
 exit_mm+0x168/0x220
 do_exit+0x62e/0x2310
 do_group_exit+0x21b/0x2d0
 __x64_sys_exit_group+0x3f/0x40
 x64_sys_call+0x2210/0x2210
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f26eb39acb9
Code: Unable to access opcode bytes at 0x7f26eb39ac8f.
RSP: 002b:00007ffe6c262148 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f26eb39acb9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffe6c2621ac R08: 0000000000000000 R09: 00000000000927c0
R10: 0000000000000006 R11: 0000000000000246 R12: 0000000000000503
R13: 00000000000927c0 R14: 000000000004a2d4 R15: 00007ffe6c262200
 </TASK>
