INFO: task kworker/1:0:31 blocked for more than 122 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:0     state:D stack:0     pid:31    tgid:31    ppid:2      flags:0x00004000
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:6026 [inline]
 __schedule+0x14ce/0x2100 kernel/sched/core.c:7893
 __schedule_loop kernel/sched/core.c:7974 [inline]
 schedule+0xc5/0x240 kernel/sched/core.c:7989
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:8046
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x960/0x1bc0 kernel/locking/mutex.c:805
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1136
 mutex_lock+0x113/0x1d0 kernel/locking/mutex.c:285
 usb_audio_probe+0x39d/0x1d60 sound/usb/card.c:887
 usb_probe_interface+0x6ac/0xc00 drivers/usb/core/driver.c:400
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x2d5/0x890 drivers/base/dd.c:657
 __driver_probe_device+0x198/0x280 drivers/base/dd.c:799
 driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
 __device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
 bus_for_each_drv+0x267/0x300 drivers/base/bus.c:459
 __device_attach+0x2c9/0x3c0 drivers/base/dd.c:1029
 device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
 bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
 device_add+0x80c/0xbf0 drivers/base/core.c:3692
 usb_set_configuration+0x1acf/0x20b0 drivers/usb/core/message.c:2268
 usb_generic_driver_probe+0x95/0x160 drivers/usb/core/generic.c:254
 usb_probe_device+0x1d4/0x380 drivers/usb/core/driver.c:295
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x2d5/0x890 drivers/base/dd.c:657
 __driver_probe_device+0x198/0x280 drivers/base/dd.c:799
 driver_probe_device+0x54/0x3f0 drivers/base/dd.c:829
 __device_attach_driver+0x2f1/0x4b0 drivers/base/dd.c:957
 bus_for_each_drv+0x267/0x300 drivers/base/bus.c:459
 __device_attach+0x2c9/0x3c0 drivers/base/dd.c:1029
 device_initial_probe+0x1e/0x30 drivers/base/dd.c:1078
 bus_probe_device+0x18b/0x270 drivers/base/bus.c:534
 device_add+0x80c/0xbf0 drivers/base/core.c:3692
 usb_new_device+0x9f8/0x15b0 drivers/usb/core/hub.c:2703
 hub_port_connect drivers/usb/core/hub.c:5574 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5714 [inline]
 port_event drivers/usb/core/hub.c:5878 [inline]
 hub_event+0x30c6/0x4700 drivers/usb/core/hub.c:5960
 process_one_work kernel/workqueue.c:3261 [inline]
 process_scheduled_works+0x7d4/0x1020 kernel/workqueue.c:3342
 worker_thread+0xc51/0x1370 kernel/workqueue.c:3423
 kthread+0x2c9/0x370 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 e03fbc6124da4a57803765f8722a1660bebc163f
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x140/0x1c0 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2ba/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x142/0x2c0 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:41
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:267 [inline]
 watchdog+0xdad/0xf00 kernel/hung_task.c:423
 kthread+0x2c9/0x370 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 312 Comm: kworker/1:3 Not tainted syzkaller #0 e03fbc6124da4a57803765f8722a1660bebc163f
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:__netif_receive_skb_core+0x34d7/0x3ab0 net/core/dev.c:5791
Code: 24 00 02 00 00 48 8b 84 24 e8 00 00 00 42 80 3c 28 00 74 08 4c 89 f7 e8 57 d6 58 fd 49 89 1e 48 8b 44 24 60 42 c6 44 28 24 f8 <42> c6 44 28 20 f8 48 c7 84 24 00 01 00 00 0e 36 e0 45 4a c7 04 28
RSP: 0018:ffffc900002303a0 EFLAGS: 00000246
RAX: 1ffff92000046094 RBX: ffff888142286dc0 RCX: dffffc0000000000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000230630 R08: ffff8881083adf00 R09: 0000000000000002
R10: 000000000000a888 R11: 0000000000000100 R12: 0000000000000001
R13: dffffc0000000000 R14: ffffc90000230678 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff47a76ffc CR3: 000000010c782000 CR4: 00000000003526b0
Call Trace:
 <IRQ>
 __netif_receive_skb_one_core net/core/dev.c:5799 [inline]
 __netif_receive_skb net/core/dev.c:5914 [inline]
 netif_receive_skb_internal net/core/dev.c:6000 [inline]
 netif_receive_skb+0xe0/0x7b0 net/core/dev.c:6059
 br_netif_receive_skb net/bridge/br_input.c:30 [inline]
 NF_HOOK include/linux/netfilter.h:317 [inline]
 br_pass_frame_up+0x126/0x1b0 net/bridge/br_input.c:70
 br_handle_frame_finish+0x120c/0x17a0 net/bridge/br_input.c:221
 nf_hook_bridge_pre net/bridge/br_input.c:301 [inline]
 br_handle_frame+0x5a6/0xba0 net/bridge/br_input.c:424
 __netif_receive_skb_core+0xfb1/0x3ab0 net/core/dev.c:5695
 __netif_receive_skb_one_core net/core/dev.c:5799 [inline]
 __netif_receive_skb net/core/dev.c:5914 [inline]
 process_backlog+0x3e5/0xad0 net/core/dev.c:6250
 __napi_poll+0xd0/0x610 net/core/dev.c:6901
 napi_poll net/core/dev.c:6970 [inline]
 net_rx_action+0x5ea/0xd80 net/core/dev.c:7092
 handle_softirqs+0x1aa/0x630 kernel/softirq.c:621
 __do_softirq+0xf/0x16 kernel/softirq.c:659
 do_softirq+0xb8/0x110 kernel/softirq.c:503
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x74/0x80 kernel/softirq.c:430
 __raw_write_unlock_bh include/linux/rwlock_api_smp.h:281 [inline]
 _raw_write_unlock_bh+0x33/0x70 kernel/locking/spinlock.c:366
 neigh_periodic_work+0xa73/0xbc0 net/core/neighbour.c:1024
 process_one_work kernel/workqueue.c:3261 [inline]
 process_scheduled_works+0x7d4/0x1020 kernel/workqueue.c:3342
 worker_thread+0xc51/0x1370 kernel/workqueue.c:3423
 kthread+0x2c9/0x370 kernel/kthread.c:389
 ret_from_fork+0x67/0xa0 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
net_ratelimit: 94366 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:9d:b0:5d:3d:07, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:9d:b0:5d:3d:07, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:1b, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:9d:b0:5d:3d:07, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:9d:b0:5d:3d:07, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:82:9d:b0:5d:3d:07, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)