======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
kworker/u8:1/13 is trying to acquire lock:
ffffffff8ec848e0 (fs_reclaim){+.+.}-{0:0}, at: might_alloc include/linux/sched/mm.h:317 [inline]
ffffffff8ec848e0 (fs_reclaim){+.+.}-{0:0}, at: slab_pre_alloc_hook mm/slub.c:4537 [inline]
ffffffff8ec848e0 (fs_reclaim){+.+.}-{0:0}, at: slab_alloc_node mm/slub.c:4897 [inline]
ffffffff8ec848e0 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_cache_noprof+0x61/0x660 mm/slub.c:5485

but task is already holding lock:
ffffffff8f5e4320 (gdp_mutex){+.+.}-{4:4}, at: get_device_parent+0x16f/0x3a0 drivers/base/core.c:3334

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #9 (gdp_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
       get_device_parent+0x16f/0x3a0 drivers/base/core.c:3334
       device_add+0x2d4/0xb80 drivers/base/core.c:3681
       device_create_groups_vargs drivers/base/core.c:4454 [inline]
       device_create+0x269/0x300 drivers/base/core.c:4493
       msr_device_create+0x33/0x50 arch/x86/kernel/msr.c:251
       cpuhp_invoke_callback+0x434/0x810 kernel/cpu.c:194
       cpuhp_thread_fun+0x362/0x780 kernel/cpu.c:1109
       smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
       kthread+0x388/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #8 (cpuhp_state-up){+.+.}-{0:0}:
       cpuhp_lock_acquire kernel/cpu.c:103 [inline]
       cpuhp_thread_fun+0x127/0x780 kernel/cpu.c:1086
       smpboot_thread_fn+0x57c/0xa80 kernel/smpboot.c:160
       kthread+0x388/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #7 (cpu_hotplug_lock){++++}-{0:0}:
       percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline]
       percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
       cpus_read_lock+0x42/0x160 kernel/cpu.c:490
       static_key_slow_inc+0x12/0x30 kernel/jump_label.c:190
       fl_create net/ipv6/ip6_flowlabel.c:451 [inline]
       ipv6_flowlabel_get net/ipv6/ip6_flowlabel.c:640 [inline]
       ipv6_flowlabel_opt+0x1cb1/0x2ae0 net/ipv6/ip6_flowlabel.c:751
       do_ipv6_setsockopt+0xdff/0x3180 net/ipv6/ipv6_sockglue.c:928
       ipv6_setsockopt+0x59/0x170 net/ipv6/ipv6_sockglue.c:965
       do_sock_setsockopt+0x17c/0x1b0 net/socket.c:2368
       __sys_setsockopt net/socket.c:2393 [inline]
       __do_sys_setsockopt net/socket.c:2399 [inline]
       __se_sys_setsockopt net/socket.c:2396 [inline]
       __x64_sys_setsockopt+0x13d/0x1b0 net/socket.c:2396
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #6 (sk_lock-AF_INET6){+.+.}-{0:0}:
       lock_sock_nested+0x41/0x100 net/core/sock.c:3828
       lock_sock include/net/sock.h:1713 [inline]
       inet_shutdown+0x6a/0x390 net/ipv4/af_inet.c:913
       nbd_mark_nsock_dead+0x2cb/0x550 drivers/block/nbd.c:318
       recv_work+0x1cee/0x1e10 drivers/block/nbd.c:1021
       process_one_work kernel/workqueue.c:3322 [inline]
       process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
       kthread+0x388/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #5 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
       nbd_handle_cmd drivers/block/nbd.c:1143 [inline]
       nbd_queue_rq+0x373/0x1150 drivers/block/nbd.c:1207
       blk_mq_dispatch_rq_list+0x499/0x1990 block/blk-mq.c:2117
       __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
       blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
       __blk_mq_sched_dispatch_requests+0xd36/0x1580 block/blk-mq-sched.c:307
       blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329
       blk_mq_run_work_fn+0x16c/0x300 block/blk-mq.c:2532
       process_one_work kernel/workqueue.c:3322 [inline]
       process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
       kthread+0x388/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #4 (&cmd->lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
       nbd_queue_rq+0xc1/0x1150 drivers/block/nbd.c:1199
       blk_mq_dispatch_rq_list+0x499/0x1990 block/blk-mq.c:2117
       __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline]
       blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline]
       __blk_mq_sched_dispatch_requests+0xd36/0x1580 block/blk-mq-sched.c:307
       blk_mq_sched_dispatch_requests+0xd7/0x190 block/blk-mq-sched.c:329
       blk_mq_run_work_fn+0x16c/0x300 block/blk-mq.c:2532
       process_one_work kernel/workqueue.c:3322 [inline]
       process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
       kthread+0x388/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #3 (set->srcu){.+.+}-{0:0}:
       srcu_lock_sync include/linux/srcu.h:199 [inline]
       __synchronize_srcu+0xc9/0x2f0 kernel/rcu/srcutree.c:1481
       elevator_switch+0x1e8/0x7b0 block/elevator.c:576
       elevator_change+0x2fa/0x480 block/elevator.c:681
       elevator_set_default+0x375/0x440 block/elevator.c:754
       blk_register_queue+0x3f3/0x4e0 block/blk-sysfs.c:992
       __add_disk+0x6cb/0xe30 block/genhd.c:524
       add_disk_fwnode+0x100/0x3a0 block/genhd.c:593
       add_disk include/linux/blkdev.h:800 [inline]
       nbd_dev_add+0x733/0xb60 drivers/block/nbd.c:2021
       nbd_init+0x15f/0x1e0 drivers/block/nbd.c:2729
       do_one_initcall+0x250/0x870 init/main.c:1347
       do_initcall_level+0x10a/0x1a0 init/main.c:1409
       do_initcalls+0x59/0xa0 init/main.c:1425
       kernel_init_freeable+0x29d/0x3e0 init/main.c:1658
       kernel_init+0x1d/0x1d0 init/main.c:1548
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (&q->elevator_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:646 [inline]
       __mutex_lock+0x19d/0x1550 kernel/locking/mutex.c:821
       elevator_change+0x1af/0x480 block/elevator.c:679
       elevator_set_none+0xb5/0x140 block/elevator.c:769
       blk_mq_elv_switch_none block/blk-mq.c:5101 [inline]
       __blk_mq_update_nr_hw_queues block/blk-mq.c:5146 [inline]
       blk_mq_update_nr_hw_queues+0x5ef/0x19f0 block/blk-mq.c:5211
       nbd_start_device+0x189/0xb30 drivers/block/nbd.c:1526
       nbd_genl_connect+0x1597/0x1c10 drivers/block/nbd.c:2276
       genl_family_rcv_msg_doit+0x233/0x340 net/netlink/genetlink.c:1114
       genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline]
       genl_rcv_msg+0x614/0x7a0 net/netlink/genetlink.c:1209
       netlink_rcv_skb+0x226/0x4a0 net/netlink/af_netlink.c:2556
       genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218
       netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
       netlink_unicast+0x7bb/0x940 net/netlink/af_netlink.c:1345
       netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1900
       sock_sendmsg_nosec+0x13a/0x180 net/socket.c:775
       __sock_sendmsg net/socket.c:790 [inline]
       ____sys_sendmsg+0x54e/0x850 net/socket.c:2684
       ___sys_sendmsg+0x2a5/0x360 net/socket.c:2738
       __sys_sendmsg net/socket.c:2770 [inline]
       __do_sys_sendmsg net/socket.c:2775 [inline]
       __se_sys_sendmsg net/socket.c:2773 [inline]
       __x64_sys_sendmsg+0x1b1/0x290 net/socket.c:2773
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&q->q_usage_counter(io)#50){++++}-{0:0}:
       blk_alloc_queue+0x544/0x690 block/blk-core.c:504
       blk_mq_alloc_queue block/blk-mq.c:4420 [inline]
       __blk_mq_alloc_disk+0x194/0x390 block/blk-mq.c:4467
       nbd_dev_add+0x494/0xb60 drivers/block/nbd.c:1991
       nbd_init+0x15f/0x1e0 drivers/block/nbd.c:2729
       do_one_initcall+0x250/0x870 init/main.c:1347
       do_initcall_level+0x10a/0x1a0 init/main.c:1409
       do_initcalls+0x59/0xa0 init/main.c:1425
       kernel_init_freeable+0x29d/0x3e0 init/main.c:1658
       kernel_init+0x1d/0x1d0 init/main.c:1548
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #0 (fs_reclaim){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3165 [inline]
       check_prevs_add kernel/locking/lockdep.c:3284 [inline]
       validate_chain kernel/locking/lockdep.c:3908 [inline]
       __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
       __fs_reclaim_acquire mm/page_alloc.c:4329 [inline]
       fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4343
       might_alloc include/linux/sched/mm.h:317 [inline]
       slab_pre_alloc_hook mm/slub.c:4537 [inline]
       slab_alloc_node mm/slub.c:4897 [inline]
       __kmalloc_cache_noprof+0x61/0x660 mm/slub.c:5485
       _kmalloc_noprof include/linux/slab.h:988 [inline]
       _kzalloc_noprof include/linux/slab.h:1309 [inline]
       class_dir_create_and_add drivers/base/core.c:3291 [inline]
       get_device_parent+0x255/0x3a0 drivers/base/core.c:3351
       device_add+0x2d4/0xb80 drivers/base/core.c:3681
       netdev_register_kobject+0x178/0x310 net/core/net-sysfs.c:2337
       register_netdevice+0x1433/0x1eb0 net/core/dev.c:11446
       nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1070 [inline]
       nsim_create+0xbd7/0x1150 drivers/net/netdevsim/netdev.c:1152
       __nsim_dev_port_add+0x7f8/0xcd0 drivers/net/netdevsim/dev.c:1509
       nsim_dev_port_add_all+0x37/0xf0 drivers/net/netdevsim/dev.c:1570
       nsim_dev_reload_create drivers/net/netdevsim/dev.c:1622 [inline]
       nsim_dev_reload_up+0x4dd/0x880 drivers/net/netdevsim/dev.c:1058
       devlink_reload+0x4b2/0x890 net/devlink/dev.c:475
       devlink_pernet_pre_exit+0x1ff/0x420 net/devlink/core.c:560
       ops_pre_exit_list net/core/net_namespace.c:161 [inline]
       ops_undo_list+0x17d/0x8d0 net/core/net_namespace.c:234
       cleanup_net+0x572/0x810 net/core/net_namespace.c:702
       process_one_work kernel/workqueue.c:3322 [inline]
       process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
       worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
       kthread+0x388/0x470 kernel/kthread.c:436
       ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

Chain exists of:
  fs_reclaim --> cpuhp_state-up --> gdp_mutex

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(gdp_mutex);
                               lock(cpuhp_state-up);
                               lock(gdp_mutex);
  lock(fs_reclaim);

 *** DEADLOCK ***

7 locks held by kworker/u8:1/13:
 #0: ffff88801c28e140 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #0: ffff88801c28e140 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #1: ffffc90000127c40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3297 [inline]
 #1: ffffc90000127c40 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa20/0x14e0 kernel/workqueue.c:3405
 #2: ffffffff9001eb48 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf5/0x810 net/core/net_namespace.c:673
 #3: ffff88801b146128 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline]
 #3: ffff88801b146128 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:124 [inline]
 #3: ffff88801b146128 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x420 net/devlink/core.c:557
 #4: ffff88801b147258 (&devlink->lock_key#9){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:292 [inline]
 #4: ffff88801b147258 (&devlink->lock_key#9){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:125 [inline]
 #4: ffff88801b147258 (&devlink->lock_key#9){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x142/0x420 net/devlink/core.c:557
 #5: ffffffff9002d700 (rtnl_mutex){+.+.}-{4:4}, at: nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1058 [inline]
 #5: ffffffff9002d700 (rtnl_mutex){+.+.}-{4:4}, at: nsim_create+0x87f/0x1150 drivers/net/netdevsim/netdev.c:1152
 #6: ffffffff8f5e4320 (gdp_mutex){+.+.}-{4:4}, at: get_device_parent+0x16f/0x3a0 drivers/base/core.c:3334

stack backtrace:
CPU: 0 UID: 0 PID: 13 Comm: kworker/u8:1 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
 check_prev_add kernel/locking/lockdep.c:3165 [inline]
 check_prevs_add kernel/locking/lockdep.c:3284 [inline]
 validate_chain kernel/locking/lockdep.c:3908 [inline]
 __lock_acquire+0x1520/0x2cf0 kernel/locking/lockdep.c:5237
 lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
 __fs_reclaim_acquire mm/page_alloc.c:4329 [inline]
 fs_reclaim_acquire+0x71/0x100 mm/page_alloc.c:4343
 might_alloc include/linux/sched/mm.h:317 [inline]
 slab_pre_alloc_hook mm/slub.c:4537 [inline]
 slab_alloc_node mm/slub.c:4897 [inline]
 __kmalloc_cache_noprof+0x61/0x660 mm/slub.c:5485
 _kmalloc_noprof include/linux/slab.h:988 [inline]
 _kzalloc_noprof include/linux/slab.h:1309 [inline]
 class_dir_create_and_add drivers/base/core.c:3291 [inline]
 get_device_parent+0x255/0x3a0 drivers/base/core.c:3351
 device_add+0x2d4/0xb80 drivers/base/core.c:3681
 netdev_register_kobject+0x178/0x310 net/core/net-sysfs.c:2337
 register_netdevice+0x1433/0x1eb0 net/core/dev.c:11446
 nsim_init_netdevsim drivers/net/netdevsim/netdev.c:1070 [inline]
 nsim_create+0xbd7/0x1150 drivers/net/netdevsim/netdev.c:1152
 __nsim_dev_port_add+0x7f8/0xcd0 drivers/net/netdevsim/dev.c:1509
 nsim_dev_port_add_all+0x37/0xf0 drivers/net/netdevsim/dev.c:1570
 nsim_dev_reload_create drivers/net/netdevsim/dev.c:1622 [inline]
 nsim_dev_reload_up+0x4dd/0x880 drivers/net/netdevsim/dev.c:1058
 devlink_reload+0x4b2/0x890 net/devlink/dev.c:475
 devlink_pernet_pre_exit+0x1ff/0x420 net/devlink/core.c:560
 ops_pre_exit_list net/core/net_namespace.c:161 [inline]
 ops_undo_list+0x17d/0x8d0 net/core/net_namespace.c:234
 cleanup_net+0x572/0x810 net/core/net_namespace.c:702
 process_one_work kernel/workqueue.c:3322 [inline]
 process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405
 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
bridge_slave_1: left allmulticast mode
bridge_slave_1: left promiscuous mode
bridge0: port 2(bridge_slave_1) entered disabled state
bridge_slave_0: left allmulticast mode
bridge_slave_0: left promiscuous mode
bridge0: port 1(bridge_slave_0) entered disabled state
bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
bond0 (unregistering): Released all slaves
hsr_slave_0: left promiscuous mode
hsr_slave_1: left promiscuous mode
batman_adv: batadv0: Interface deactivated: batadv_slave_0
batman_adv: batadv0: Removing interface: batadv_slave_0
batman_adv: batadv0: Interface deactivated: batadv_slave_1
batman_adv: batadv0: Removing interface: batadv_slave_1
veth1_macvtap: left promiscuous mode
veth0_macvtap: left promiscuous mode
veth1_vlan: left promiscuous mode
veth0_vlan: left promiscuous mode
team0 (unregistering): Port device team_slave_1 removed
team0 (unregistering): Port device team_slave_0 removed
netdevsim netdevsim2 netdevsim3 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim2 netdevsim2 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim2 netdevsim1 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
netdevsim netdevsim2 netdevsim0 (unregistering): unset [1, 0] type 2 family 0 port 6081 - 0
bridge_slave_1: left allmulticast mode
bridge_slave_1: left promiscuous mode
bridge0: port 2(bridge_slave_1) entered disabled state
bridge_slave_0: left allmulticast mode
bridge_slave_0: left promiscuous mode
bridge0: port 1(bridge_slave_0) entered disabled state
bond0 (unregistering): (slave bond_slave_0): Releasing backup interface
bond0 (unregistering): (slave bond_slave_1): Releasing backup interface
bond0 (unregistering): Released all slaves
tipc: Left network mode
hsr_slave_0: left promiscuous mode
hsr_slave_1: left promiscuous mode
batman_adv: batadv0: Interface deactivated: batadv_slave_0
batman_adv: batadv0: Removing interface: batadv_slave_0
batman_adv: batadv0: Interface deactivated: batadv_slave_1
batman_adv: batadv0: Removing interface: batadv_slave_1
veth1_macvtap: left promiscuous mode
veth0_macvtap: left promiscuous mode
veth1_vlan: left promiscuous mode
veth0_vlan: left promiscuous mode
team0 (unregistering): Port device team_slave_1 removed
team0 (unregistering): Port device team_slave_0 removed
IPVS: stop unused estimator thread 0...
bridge0: port 1(bridge_slave_0) entered blocking state
bridge0: port 1(bridge_slave_0) entered forwarding state
bridge0: port 2(bridge_slave_1) entered blocking state
bridge0: port 2(bridge_slave_1) entered forwarding state