netlink: 52 bytes leftover after parsing attributes in process `syz.0.4197'.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.4197/19976 is trying to acquire lock:
ffffffff8ea85520 (fs_reclaim){+.+.}-{0:0}, at: kmem_cache_alloc_node_noprof+0x4a/0x690

but task is already holding lock:
ffff888020006530 (&idev->mc_lock){+.+.}-{4:4}, at: __ipv6_dev_mc_dec+0x39/0x330

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #7 (&idev->mc_lock){+.+.}-{4:4}:
       __mutex_lock+0x1a3/0x1550
       __ipv6_dev_mc_inc+0x4e/0xa50
       __ipv6_sock_mc_join+0x503/0x750
       ipv6_mcast_join_leave+0x1a2/0x240
       do_ipv6_setsockopt+0x190e/0x3150
       ipv6_setsockopt+0x59/0x170
       do_sock_setsockopt+0x17c/0x1b0
       __x64_sys_setsockopt+0x13d/0x1b0
       do_syscall_64+0x15f/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_sock_nested+0x41/0x100
       inet_shutdown+0x6a/0x390
       nbd_mark_nsock_dead+0x2e9/0x560
       sock_shutdown+0x15e/0x260
       nbd_clear_sock+0x24/0x170
       nbd_config_put+0x2dd/0x580
       nbd_genl_connect+0x19d5/0x1cf0
       genl_family_rcv_msg_doit+0x22a/0x330
       genl_rcv_msg+0x61c/0x7a0
       netlink_rcv_skb+0x232/0x4b0
       genl_rcv+0x28/0x40
       netlink_unicast+0x75c/0x8e0
       netlink_sendmsg+0x813/0xb40
       ____sys_sendmsg+0x972/0x9f0
       ___sys_sendmsg+0x2a5/0x360
       __x64_sys_sendmsg+0x1bd/0x2a0
       do_syscall_64+0x15f/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock+0x1a3/0x1550
       nbd_queue_rq+0x37b/0x1100
       blk_mq_dispatch_rq_list+0xa70/0x1910
       __blk_mq_sched_dispatch_requests+0xdcc/0x1600
       blk_mq_sched_dispatch_requests+0xd7/0x190
       blk_mq_run_hw_queue+0x348/0x4f0
       blk_mq_dispatch_list+0xd16/0xe10
       blk_mq_flush_plug_list+0x48d/0x570
       __blk_flush_plug+0x3ed/0x4d0
       __submit_bio+0x28d/0x580
       submit_bio_noacct_nocheck+0x2f4/0xa40
       block_read_full_folio+0x599/0x830
       filemap_read_folio+0x137/0x3b0
       do_read_cache_folio+0x358/0x590
       read_part_sector+0xb6/0x2b0
       adfspart_check_ICS+0xb1/0x960
       bdev_disk_changed+0x817/0x1770
       blkdev_get_whole+0x380/0x510
       bdev_open+0x31e/0xd30
       blkdev_open+0x470/0x610
       do_dentry_open+0x785/0x14e0
       vfs_open+0x3b/0x340
       path_openat+0x2e08/0x3860
       do_file_open+0x23e/0x4a0
       do_sys_openat2+0x113/0x200
       __x64_sys_openat+0x138/0x170
       do_syscall_64+0x15f/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (&cmd->lock){+.+.}-{4:4}:
       __mutex_lock+0x1a3/0x1550
       nbd_queue_rq+0xc6/0x1100
       blk_mq_dispatch_rq_list+0xa70/0x1910
       __blk_mq_sched_dispatch_requests+0xdcc/0x1600
       blk_mq_sched_dispatch_requests+0xd7/0x190
       blk_mq_run_hw_queue+0x348/0x4f0
       blk_mq_dispatch_list+0xd16/0xe10
       blk_mq_flush_plug_list+0x48d/0x570
       __blk_flush_plug+0x3ed/0x4d0
       __submit_bio+0x28d/0x580
       submit_bio_noacct_nocheck+0x2f4/0xa40
       block_read_full_folio+0x599/0x830
       filemap_read_folio+0x137/0x3b0
       do_read_cache_folio+0x358/0x590
       read_part_sector+0xb6/0x2b0
       adfspart_check_ICS+0xb1/0x960
       bdev_disk_changed+0x817/0x1770
       blkdev_get_whole+0x380/0x510
       bdev_open+0x31e/0xd30
       blkdev_open+0x470/0x610
       do_dentry_open+0x785/0x14e0
       vfs_open+0x3b/0x340
       path_openat+0x2e08/0x3860
       do_file_open+0x23e/0x4a0
       do_sys_openat2+0x113/0x200
       __x64_sys_openat+0x138/0x170
       do_syscall_64+0x15f/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (set->srcu){.+.+}-{0:0}:
       __synchronize_srcu+0xca/0x300
       elevator_switch+0x1e8/0x7a0
       elevator_change+0x2cc/0x450
       elevator_set_default+0x36c/0x430
       blk_register_queue+0x3e9/0x4e0
       __add_disk+0x677/0xd50
       add_disk_fwnode+0xfb/0x480
       nbd_dev_add+0x72c/0xb50
       nbd_init+0x168/0x1f0
       do_one_initcall+0x250/0x870
       do_initcall_level+0x104/0x190
       do_initcalls+0x59/0xa0
       kernel_init_freeable+0x2a6/0x3e0
       kernel_init+0x1d/0x1d0
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #2 (&q->elevator_lock){+.+.}-{4:4}:
       __mutex_lock+0x1a3/0x1550
       elevator_change+0x1b3/0x450
       elevator_set_none+0xb5/0x140
       blk_mq_update_nr_hw_queues+0x5e7/0x1a60
       nbd_start_device+0x17f/0xb10
       nbd_genl_connect+0x165b/0x1cf0
       genl_family_rcv_msg_doit+0x22a/0x330
       genl_rcv_msg+0x61c/0x7a0
       netlink_rcv_skb+0x232/0x4b0
       genl_rcv+0x28/0x40
       netlink_unicast+0x75c/0x8e0
       netlink_sendmsg+0x813/0xb40
       ____sys_sendmsg+0x972/0x9f0
       ___sys_sendmsg+0x2a5/0x360
       __x64_sys_sendmsg+0x1bd/0x2a0
       do_syscall_64+0x15f/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&q->q_usage_counter(io)#50){++++}-{0:0}:
       blk_alloc_queue+0x546/0x680
       __blk_mq_alloc_disk+0x197/0x390
       nbd_dev_add+0x499/0xb50
       nbd_init+0x168/0x1f0
       do_one_initcall+0x250/0x870
       do_initcall_level+0x104/0x190
       do_initcalls+0x59/0xa0
       kernel_init_freeable+0x2a6/0x3e0
       kernel_init+0x1d/0x1d0
       ret_from_fork+0x514/0xb70
       ret_from_fork_asm+0x1a/0x30

-> #0 (fs_reclaim){+.+.}-{0:0}:
       __lock_acquire+0x15a5/0x2cf0
       lock_acquire+0x106/0x350
       fs_reclaim_acquire+0x71/0x100
       kmem_cache_alloc_node_noprof+0x4a/0x690
       __alloc_skb+0x1d0/0x7d0
       inet6_ifmcaddr_notify+0xfa/0x1e0
       __ipv6_dev_mc_dec+0x2dc/0x330
       ipv6_mc_destroy_dev+0x33c/0x5a0
       addrconf_ifdown+0x1561/0x1a40
       addrconf_notify+0x1bc/0x1050
       notifier_call_chain+0x1ad/0x3d0
       unregister_netdevice_many_notify+0x17a5/0x22c0
       unregister_netdevice_queue+0x31f/0x360
       nsim_destroy+0x277/0x7f0
       __nsim_dev_port_del+0x14f/0x200
       nsim_dev_reload_destroy+0x288/0x490
       nsim_dev_reload_down+0x8a/0xc0
       devlink_reload+0x1eb/0x8c0
       devlink_nl_reload_doit+0x9d4/0xc80
       genl_family_rcv_msg_doit+0x22a/0x330
       genl_rcv_msg+0x61c/0x7a0
       netlink_rcv_skb+0x232/0x4b0
       genl_rcv+0x28/0x40
       netlink_unicast+0x75c/0x8e0
       netlink_sendmsg+0x813/0xb40
       ____sys_sendmsg+0x972/0x9f0
       ___sys_sendmsg+0x2a5/0x360
       __x64_sys_sendmsg+0x1bd/0x2a0
       do_syscall_64+0x15f/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

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 ***

5 locks held by syz.0.4197/19976:
 #0: ffffffff8fe3f8c8 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40
 #1: ffff88801ff6a128 (&dev->mutex){....}-{4:4}, at: devlink_get_from_attrs_lock+0x34a/0x490
 #2: ffff88801ff69258 (&devlink->lock_key#3){+.+.}-{4:4}, at: devlink_get_from_attrs_lock+0x360/0x490
 #3: ffffffff8fdd0300 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x16b/0x7f0
 #4: ffff888020006530 (&idev->mc_lock){+.+.}-{4:4}, at: __ipv6_dev_mc_dec+0x39/0x330

stack backtrace:
CPU: 1 UID: 0 PID: 19976 Comm: syz.0.4197 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+0x15a5/0x2cf0
 lock_acquire+0x106/0x350
 fs_reclaim_acquire+0x71/0x100
 kmem_cache_alloc_node_noprof+0x4a/0x690
 __alloc_skb+0x1d0/0x7d0
 inet6_ifmcaddr_notify+0xfa/0x1e0
 __ipv6_dev_mc_dec+0x2dc/0x330
 ipv6_mc_destroy_dev+0x33c/0x5a0
 addrconf_ifdown+0x1561/0x1a40
 addrconf_notify+0x1bc/0x1050
 notifier_call_chain+0x1ad/0x3d0
 unregister_netdevice_many_notify+0x17a5/0x22c0
 unregister_netdevice_queue+0x31f/0x360
 nsim_destroy+0x277/0x7f0
 __nsim_dev_port_del+0x14f/0x200
 nsim_dev_reload_destroy+0x288/0x490
 nsim_dev_reload_down+0x8a/0xc0
 devlink_reload+0x1eb/0x8c0
 devlink_nl_reload_doit+0x9d4/0xc80
 genl_family_rcv_msg_doit+0x22a/0x330
 genl_rcv_msg+0x61c/0x7a0
 netlink_rcv_skb+0x232/0x4b0
 genl_rcv+0x28/0x40
 netlink_unicast+0x75c/0x8e0
 netlink_sendmsg+0x813/0xb40
 ____sys_sendmsg+0x972/0x9f0
 ___sys_sendmsg+0x2a5/0x360
 __x64_sys_sendmsg+0x1bd/0x2a0
 do_syscall_64+0x15f/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe56e19cdd9
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:00007fe56f137028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe56e415fa0 RCX: 00007fe56e19cdd9
RDX: 0000000000000030 RSI: 0000200000000100 RDI: 0000000000000004
RBP: 00007fe56e232d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe56e416038 R14: 00007fe56e415fa0 R15: 00007fff2d86acc8
 </TASK>
netdevsim netdevsim0 netdevsim3 (unregistering): unset [0, 0] type 1 family 0 port 8472 - 0
netdevsim netdevsim0 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim3 (unregistering): unset [1, 1] type 2 family 0 port 34344 - 0
netdevsim netdevsim0 netdevsim2 (unregistering): unset [0, 0] type 1 family 0 port 8472 - 0
netdevsim netdevsim0 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim2 (unregistering): unset [1, 1] type 2 family 0 port 34344 - 0
netdevsim netdevsim0 netdevsim1 (unregistering): unset [0, 0] type 1 family 0 port 8472 - 0
netdevsim netdevsim0 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim1 (unregistering): unset [1, 1] type 2 family 0 port 34344 - 0
netdevsim netdevsim0 netdevsim0 (unregistering): unset [0, 0] type 1 family 0 port 8472 - 0
netdevsim netdevsim0 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim0 netdevsim0 (unregistering): unset [1, 1] type 2 family 0 port 34344 - 0
