======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.12177/27732 is trying to acquire lock:
ffff8881b0e40530 (&idev->mc_lock){+.+.}-{4:4}, at: ip6_mc_msfilter+0x22a/0xf10

but task is already holding lock:
ffff888112cdee60 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: do_ipv6_setsockopt+0x8e0/0x3180

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #8 (k-sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_sock_nested+0x41/0x100
       __inet6_bind+0x301/0xf30
       mptcp_bind+0x110/0x1d0
       __sys_bind+0x2e3/0x410
       __x64_sys_bind+0x7a/0x90
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #7 (sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_sock_nested+0x41/0x100
       inet_shutdown+0x6a/0x390
       nbd_mark_nsock_dead+0x2cb/0x550
       recv_work+0x1cee/0x1e10
       process_scheduled_works+0xa8e/0x14e0
       worker_thread+0xa47/0xfb0
       kthread+0x388/0x470
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #6 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       nbd_queue_rq+0x373/0x1150
       blk_mq_dispatch_rq_list+0x499/0x1990
       __blk_mq_sched_dispatch_requests+0xd36/0x1580
       blk_mq_sched_dispatch_requests+0xd7/0x190
       blk_mq_run_work_fn+0x16c/0x300
       process_scheduled_works+0xa8e/0x14e0
       worker_thread+0xa47/0xfb0
       kthread+0x388/0x470
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #5 (&cmd->lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       nbd_queue_rq+0xc1/0x1150
       blk_mq_dispatch_rq_list+0x499/0x1990
       __blk_mq_sched_dispatch_requests+0xd36/0x1580
       blk_mq_sched_dispatch_requests+0xd7/0x190
       blk_mq_run_work_fn+0x16c/0x300
       process_scheduled_works+0xa8e/0x14e0
       worker_thread+0xa47/0xfb0
       kthread+0x388/0x470
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #4 (set->srcu){.+.+}-{0:0}:
       __synchronize_srcu+0xc9/0x2f0
       elevator_switch+0x1e8/0x7b0
       elevator_change+0x2fa/0x480
       elevator_set_default+0x375/0x440
       blk_register_queue+0x3f3/0x4e0
       __add_disk+0x6cb/0xe30
       add_disk_fwnode+0x100/0x3a0
       nbd_dev_add+0x733/0xb60
       nbd_init+0x15f/0x1e0
       do_one_initcall+0x250/0x870
       do_initcall_level+0x10a/0x1a0
       do_initcalls+0x59/0xa0
       kernel_init_freeable+0x29d/0x3e0
       kernel_init+0x1d/0x1d0
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #3 (&q->elevator_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       elevator_change+0x1af/0x480
       elevator_set_none+0xb5/0x140
       blk_mq_update_nr_hw_queues+0x5ef/0x19f0
       nbd_start_device+0x189/0xb30
       nbd_genl_connect+0x1597/0x1c10
       genl_family_rcv_msg_doit+0x233/0x340
       genl_rcv_msg+0x614/0x7a0
       netlink_rcv_skb+0x226/0x4a0
       genl_rcv+0x28/0x40
       netlink_unicast+0x7bb/0x940
       netlink_sendmsg+0x813/0xb40
       sock_sendmsg_nosec+0x13a/0x180
       ____sys_sendmsg+0x54e/0x850
       ___sys_sendmsg+0x2a5/0x360
       __x64_sys_sendmsg+0x1b1/0x290
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (&q->q_usage_counter(io)#49){++++}-{0:0}:
       blk_alloc_queue+0x544/0x690
       __blk_mq_alloc_disk+0x194/0x390
       nbd_dev_add+0x494/0xb60
       nbd_init+0x15f/0x1e0
       do_one_initcall+0x250/0x870
       do_initcall_level+0x10a/0x1a0
       do_initcalls+0x59/0xa0
       kernel_init_freeable+0x29d/0x3e0
       kernel_init+0x1d/0x1d0
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #1 (fs_reclaim){+.+.}-{0:0}:
       fs_reclaim_acquire+0x71/0x100
       __kmalloc_cache_noprof+0x61/0x660
       __ipv6_dev_mc_inc+0x447/0xa40
       ipv6_add_dev+0xe36/0x13a0
       addrconf_notify+0x771/0x1050
       call_netdevice_register_net_notifiers+0x12a/0x560
       register_netdevice_notifier+0x10b/0x440
       addrconf_init+0xad/0x170
       inet6_init+0x228/0x3f0
       do_one_initcall+0x250/0x870
       do_initcall_level+0x10a/0x1a0
       do_initcalls+0x59/0xa0
       kernel_init_freeable+0x29d/0x3e0
       kernel_init+0x1d/0x1d0
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #0 (&idev->mc_lock){+.+.}-{4:4}:
       __lock_acquire+0x1520/0x2cf0
       lock_acquire+0x106/0x350
       __mutex_lock+0x19d/0x1550
       ip6_mc_msfilter+0x22a/0xf10
       ipv6_set_mcast_msfilter+0x25e/0x310
       do_ipv6_setsockopt+0x1342/0x3180
       ipv6_setsockopt+0x59/0x170
       smc_setsockopt+0x232/0xb00
       do_sock_setsockopt+0x17c/0x1b0
       __x64_sys_setsockopt+0x13d/0x1b0
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &idev->mc_lock --> sk_lock-AF_INET6 --> k-sk_lock-AF_INET6

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(k-sk_lock-AF_INET6);
                               lock(sk_lock-AF_INET6);
                               lock(k-sk_lock-AF_INET6);
  lock(&idev->mc_lock);

 *** DEADLOCK ***

2 locks held by syz.3.12177/27732:
 #0: ffff8881095db128 (&smc->clcsock_release_lock){+.+.}-{4:4}, at: smc_setsockopt+0x174/0xb00
 #1: ffff888112cdee60 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: do_ipv6_setsockopt+0x8e0/0x3180

stack backtrace:
CPU: 0 UID: 0 PID: 27732 Comm: syz.3.12177 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:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_circular_bug+0x2e1/0x300
 check_noncircular+0x12e/0x150
 __lock_acquire+0x1520/0x2cf0
 lock_acquire+0x106/0x350
 __mutex_lock+0x19d/0x1550
 ip6_mc_msfilter+0x22a/0xf10
 ipv6_set_mcast_msfilter+0x25e/0x310
 do_ipv6_setsockopt+0x1342/0x3180
 ipv6_setsockopt+0x59/0x170
 smc_setsockopt+0x232/0xb00
 do_sock_setsockopt+0x17c/0x1b0
 __x64_sys_setsockopt+0x13d/0x1b0
 do_syscall_64+0x174/0x580
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7feeffd9df99
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fef00bb7028 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007fef00025fa0 RCX: 00007feeffd9df99
RDX: 0000000000000030 RSI: 0000000000000029 RDI: 0000000000000006
RBP: 00007feeffe34ec4 R08: 0000000000020000 R09: 0000000000000000
R10: 00002000000004c0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fef00026038 R14: 00007fef00025fa0 R15: 00007ffd1854dff8
 </TASK>
netlink: 24 bytes leftover after parsing attributes in process `syz.3.12177'.
