======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
kworker/u8:6/18387 is trying to acquire lock:
ffffffff8ea848a0 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_node_track_caller_noprof+0xbc/0x730

but task is already holding lock:
ffff888192702530 (&idev->mc_lock){+.+.}-{4:4}, at: ipv6_mc_netdev_event+0xe1/0x5a0

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #8 (&idev->mc_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       __ipv6_dev_mc_inc+0x4e/0xa40
       __ipv6_sock_mc_join+0x4f7/0x740
       do_ipv6_mcast_group_source+0x3df/0x4c0
       do_ipv6_setsockopt+0x1768/0x3180
       ipv6_setsockopt+0x59/0x170
       do_sock_setsockopt+0x17c/0x1b0
       __x64_sys_setsockopt+0x13d/0x1b0
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #7 (sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_sock_nested+0x41/0x100
       tls_sw_sendmsg+0x161/0x2860
       sock_sendmsg_nosec+0x90/0x180
       __sys_sendto+0x408/0x5a0
       __x64_sys_sendto+0xde/0x100
       do_syscall_64+0x174/0x580
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (&ctx->tx_lock){+.+.}-{4:4}:
       __mutex_lock+0x19d/0x1550
       tls_sw_sendmsg+0x13c/0x2860
       sock_sendmsg_nosec+0x90/0x180
       sock_sendmsg+0x1ca/0x2d0
       __sock_xmit+0x245/0x4f0
       nbd_disconnect+0x3ad/0x560
       nbd_disconnect_and_put+0x32/0x280
       nbd_genl_disconnect+0x4af/0x590
       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

-> #5 (&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

-> #4 (&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

-> #3 (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+0xfb/0x4b0
       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

-> #2 (&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

-> #1 (&q->q_usage_counter(io)#57){++++}-{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

-> #0 (fs_reclaim){+.+.}-{0:0}:
       __lock_acquire+0x1520/0x2cf0
       lock_acquire+0x106/0x350
       fs_reclaim_acquire+0x71/0x100
       __kmalloc_node_track_caller_noprof+0xbc/0x730
       __alloc_skb+0x2bd/0x7a0
       mld_newpack+0x165/0xcb0
       add_grec+0x119f/0x19d0
       mld_send_report+0x1ed/0x380
       ipv6_mc_netdev_event+0x1b7/0x5a0
       notifier_call_chain+0x1a5/0x3d0
       call_netdevice_notifiers+0x90/0xd0
       bond_resend_igmp_join_requests_delayed+0x61/0x170
       process_scheduled_works+0xa8e/0x14e0
       worker_thread+0xa47/0xfb0
       kthread+0x388/0x470
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

other info that might help us debug this:

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

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

4 locks held by kworker/u8:6/18387:
 #0: ffff888113da9940 ((wq_completion)bond0#6){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #1: ffffc9000b3a7c40 ((work_completion)(&(&bond->mcast_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0
 #2: ffffffff8fded380 (rtnl_mutex){+.+.}-{4:4}, at: bond_resend_igmp_join_requests_delayed+0x23/0x170
 #3: ffff888192702530 (&idev->mc_lock){+.+.}-{4:4}, at: ipv6_mc_netdev_event+0xe1/0x5a0

stack backtrace:
CPU: 1 UID: 0 PID: 18387 Comm: kworker/u8:6 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: bond0 bond_resend_igmp_join_requests_delayed
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
 fs_reclaim_acquire+0x71/0x100
 __kmalloc_node_track_caller_noprof+0xbc/0x730
 __alloc_skb+0x2bd/0x7a0
 mld_newpack+0x165/0xcb0
 add_grec+0x119f/0x19d0
 mld_send_report+0x1ed/0x380
 ipv6_mc_netdev_event+0x1b7/0x5a0
 notifier_call_chain+0x1a5/0x3d0
 call_netdevice_notifiers+0x90/0xd0
 bond_resend_igmp_join_requests_delayed+0x61/0x170
 process_scheduled_works+0xa8e/0x14e0
 worker_thread+0xa47/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x514/0xb70
 ret_from_fork_asm+0x1a/0x30
 </TASK>
batman_adv: batadv0: Local translation table size (92) exceeds maximum packet size (0); Ignoring new local tt entry: 33:33:ff:aa:aa:2a
batman_adv: batadv0: Local translation table size (92) exceeds maximum packet size (0); Ignoring new local tt entry: 01:00:5e:00:00:01
batman_adv: batadv0: Local translation table size (92) exceeds maximum packet size (0); Ignoring new local tt entry: 33:33:ff:aa:aa:2a
batman_adv: batadv0: Local translation table size (92) exceeds maximum packet size (0); Ignoring new local tt entry: 01:00:5e:00:00:01
