INFO: task syz.3.845:3252 blocked for more than 122 seconds.
      Not tainted 6.12.38-syzkaller-g2b955c7a0f73 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.845       state:D stack:0     pid:3252  tgid:3251  ppid:291    flags:0x00000004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5945 [inline]
 __schedule+0x1322/0x1df0 kernel/sched/core.c:7791
 __schedule_loop kernel/sched/core.c:7872 [inline]
 schedule+0xc6/0x240 kernel/sched/core.c:7887
 schedule_preempt_disabled+0x14/0x30 kernel/sched/core.c:7944
 __mutex_lock_common kernel/locking/mutex.c:707 [inline]
 __mutex_lock+0x81e/0x1b50 kernel/locking/mutex.c:803
 __mutex_lock_slowpath+0xe/0x20 kernel/locking/mutex.c:1134
 mutex_lock+0x102/0x1c0 kernel/locking/mutex.c:285
 device_lock include/linux/device.h:908 [inline]
 usbdev_open+0x171/0x840 drivers/usb/core/devio.c:1051
 chrdev_open+0x4db/0x5f0 fs/char_dev.c:414
 do_dentry_open+0x978/0x1510 fs/open.c:960
 vfs_open+0x86/0x230 fs/open.c:1090
 do_open fs/namei.c:3774 [inline]
 path_openat+0x2b6c/0x34b0 fs/namei.c:3933
 do_filp_open+0x1c6/0x3e0 fs/namei.c:3960
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1438
 do_sys_open fs/open.c:1453 [inline]
 __do_sys_openat fs/open.c:1469 [inline]
 __se_sys_openat fs/open.c:1464 [inline]
 __x64_sys_openat+0x13a/0x170 fs/open.c:1464
 x64_sys_call+0xe69/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x58/0xf0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f364838d550
RSP: 002b:00007f3649151b70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000082 RCX: 00007f364838d550
RDX: 0000000000000082 RSI: 00007f3649151c10 RDI: 00000000ffffff9c
RBP: 00007f3649151c10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd
R13: 00007f36485b6038 R14: 00007f36485b5fa0 R15: 00007ffeb8b10318
 </TASK>
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 37 Comm: khungtaskd Not tainted 6.12.38-syzkaller-g2b955c7a0f73 #0 b45819abec46ddf88869a165aa8765f6075b6315
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 __dump_stack+0x21/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x10c/0x190 lib/dump_stack.c:120
 dump_stack+0x19/0x20 lib/dump_stack.c:129
 nmi_cpu_backtrace+0x2bf/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+0xd8f/0xed0 kernel/hung_task.c:423
 kthread+0x2ca/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: 382 Comm: kworker/1:4 Not tainted 6.12.38-syzkaller-g2b955c7a0f73 #0 b45819abec46ddf88869a165aa8765f6075b6315
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:br_handle_frame_finish+0x0/0x1720 net/bridge/br_input.c:77
Code: 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc b8 cf d5 82 21 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48
RSP: 0018:ffffc900002308d8 EFLAGS: 00000246
RAX: ffffffff84ffa3a7 RBX: ffff888141315280 RCX: ffff8881319e8000
RDX: ffff888141315280 RSI: 00000000aaaa9fbb RDI: 0000000000000000
RBP: ffffc90000230950 R08: ffff8881413152b7 R09: 0000000000000000
R10: ffff8881413152a8 R11: ffffed1028262a57 R12: dffffc0000000000
R13: ffff88811b1ad000 R14: 0000000000000eaa R15: ffff88811e8bdf2c
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fad2d0a0f70 CR3: 000000010cb4c000 CR4: 00000000003526b0
Call Trace:
 <IRQ>
 __netif_receive_skb_core+0xf48/0x3940 net/core/dev.c:5651
 __netif_receive_skb_one_core net/core/dev.c:5755 [inline]
 __netif_receive_skb net/core/dev.c:5870 [inline]
 process_backlog+0x3e5/0xae0 net/core/dev.c:6206
 __napi_poll+0xd0/0x610 net/core/dev.c:6857
 napi_poll net/core/dev.c:6926 [inline]
 net_rx_action+0x584/0xce0 net/core/dev.c:7048
 handle_softirqs+0x1ab/0x630 kernel/softirq.c:621
 __do_softirq+0xf/0x16 kernel/softirq.c:659
 do_softirq+0xa6/0x100 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:1019
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x7d2/0x1020 kernel/workqueue.c:3319
 worker_thread+0xc58/0x1250 kernel/workqueue.c:3400
 kthread+0x2ca/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: 67224 callbacks suppressed
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:36:10:ee:e3:29:77, 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 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:aa:aa:aa:aa:aa:0c, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:36:10:ee:e3:29:77, 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 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:36:10:ee:e3:29:77, vlan:0)
bridge0: received packet on bridge_slave_0 with own address as source address (addr:aa:aa:aa:aa:aa:0c, vlan:0)