INFO: task syz.3.52:6369 blocked for more than 143 seconds.
      Tainted: G        W           syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.52        state:D stack:28632 pid:6369  tgid:6336  ppid:5840   task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5357 [inline]
 __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
 __schedule_loop kernel/sched/core.c:7043 [inline]
 rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339
 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline]
 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline]
 __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760
 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800
 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline]
 rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244
 inode_lock include/linux/fs.h:869 [inline]
 open_last_lookups fs/namei.c:3804 [inline]
 path_openat+0x8e6/0x3840 fs/namei.c:4043
 do_filp_open+0x1fa/0x410 fs/namei.c:4073
 do_sys_openat2+0x121/0x1c0 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_open fs/open.c:1458 [inline]
 __se_sys_open fs/open.c:1454 [inline]
 __x64_sys_open+0x11e/0x150 fs/open.c:1454
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f638aa0ebe9
RSP: 002b:00007f6388c4d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f638ac36090 RCX: 00007f638aa0ebe9
RDX: 389b0d52417bb201 RSI: 0000000000064842 RDI: 00002000000005c0
RBP: 00007f638aa91e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f638ac36128 R14: 00007f638ac36090 R15: 00007fff52b48488
 </TASK>
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Tainted: G        W           syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
 watchdog+0xf93/0xfe0 kernel/hung_task.c:491
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 49 Comm: kworker/1:1 Tainted: G        W           syzkaller #0 PREEMPT_{RT,(full)} 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: events_power_efficient neigh_periodic_work
RIP: 0010:preempt_count_add+0x5a/0x1a0 kernel/sched/core.c:5829
Code: 17 00 75 07 65 8b 05 e5 f2 65 10 65 01 3d de f2 65 10 48 c7 c0 40 e3 00 99 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 ec 00 00 00 <83> 3d cf 25 71 17 00 75 11 65 8b 05 b6 f2 65 10 0f b6 c0 3d f5 00
RSP: 0018:ffffc90000bb7820 EFLAGS: 00000097
RAX: 0000000000000004 RBX: ffffffff8ede2e28 RCX: ffffffff9900e303
RDX: 0000000000000000 RSI: ffffffff8b620c60 RDI: 0000000000000001
RBP: ffffc90000bb78d0 R08: ffffffff8f1d3e37 R09: 1ffffffff1e3a7c6
R10: dffffc0000000000 R11: fffffbfff1e3a7c7 R12: dffffc0000000000
R13: ffffffff8ede2e28 R14: 0000000000000a02 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8881269c5000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc3c2862b32 CR3: 0000000026bee000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:109 [inline]
 _raw_spin_lock_irqsave+0x8c/0xf0 kernel/locking/spinlock.c:162
 rt_mutex_slowunlock+0xb0/0x8a0 kernel/locking/rtmutex.c:1417
 write_unlock_bh include/linux/rwlock_rt.h:133 [inline]
 neigh_periodic_work+0xc25/0xe90 net/core/neighbour.c:1040
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>