============================================
WARNING: possible recursive locking detected
syzkaller #0 Not tainted
--------------------------------------------
kworker/0:2/1277 is trying to acquire lock:
ffff88801e53cf30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360

but task is already holding lock:
ffff8880276d0f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360

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

       CPU0
       ----
  lock(&hsr->seqnr_lock);
  lock(&hsr->seqnr_lock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

13 locks held by kworker/0:2/1277:
 #0: ffff888107ca7d48 ((wq_completion)mld){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900075cfbc0 ((work_completion)(&(&idev->mc_ifc_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888119d85538 (&idev->mc_lock){+.+.}-{4:4}, at: mld_ifc_work+0x2d/0xd60
 #3: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: mld_sendpack+0x1e7/0xe60
 #4: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: ip6_output+0x126/0x550
 #5: ffffffff8e13a140 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27b/0x3b50
 #6: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360
 #7: ffff8880276d0f30 (&hsr->seqnr_lock){+.-.}-{3:3}, at: hsr_dev_xmit+0x237/0x360
 #8: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: hsr_forward_skb+0x9e/0x2860
 #9: ffffffff8e13a140 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27b/0x3b50
 #10: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: br_dev_xmit+0x185/0x1840
 #11: ffffffff8e13a140 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x27b/0x3b50
 #12: ffffffff8e13a0e0 (rcu_read_lock){....}-{1:3}, at: hsr_dev_xmit+0x2d/0x360

stack backtrace:
CPU: 0 UID: 0 PID: 1277 Comm: kworker/0:2 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_bh+0x36/0x50
 hsr_dev_xmit+0x237/0x360
 dev_hard_start_xmit+0x2d7/0x830
 __dev_queue_xmit+0x1b8d/0x3b50
 br_dev_queue_push_xmit+0x6c5/0x890
 NF_HOOK+0x320/0x3c0
 br_forward_finish+0xd3/0x130
 NF_HOOK+0x320/0x3c0
 __br_forward+0x41e/0x600
 maybe_deliver+0xb5/0x160
 br_flood+0x31a/0x6a0
 br_dev_xmit+0x11b3/0x1840
 dev_hard_start_xmit+0x2d7/0x830
 __dev_queue_xmit+0x1b8d/0x3b50
 hsr_forward_skb+0x158b/0x2860
 hsr_dev_xmit+0x242/0x360
 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+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
 </TASK>
