rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 ticks this GP) idle=923/1/0x4000000000000000 softirq=6901/6901 fqs=203 
	(detected by 0, t=10502 jiffies, g=6753, q=3957)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 1486 Comm: kworker/u4:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events_unbound fsnotify_connector_destroy_workfn
RIP: 0010:__lock_acquire+0x3c3/0x7c60 kernel/locking/lockdep.c:-1
Code: 44 24 20 4c 89 64 24 78 49 8d 7c 24 08 48 89 f8 48 c1 e8 03 42 80 3c 00 00 74 0f e8 97 32 60 00 49 b8 00 00 00 00 00 fc ff df <48> 8b 44 24 78 4c 89 78 08 49 89 c7 48 8d 78 10 48 89 f8 48 c1 e8
RSP: 0018:ffffc90000dd0860 EFLAGS: 00000046
RAX: 1ffff110046e1526 RBX: ffffffff962f3430 RCX: 1ffff110046e1529
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88802370a930
RBP: ffffc90000dd0ab0 R08: dffffc0000000000 R09: 0000000000000001
R10: fffffbfff1ad323e R11: 1ffffffff1ad323d R12: ffff88802370a928
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff83df1c83
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff53852e18 CR3: 0000000073790000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa4/0xf0 kernel/locking/spinlock.c:162
 debug_object_deactivate+0x63/0x340 lib/debugobjects.c:749
 debug_hrtimer_deactivate kernel/time/hrtimer.c:415 [inline]
 debug_deactivate+0x1d/0x1c0 kernel/time/hrtimer.c:471
 __run_hrtimer kernel/time/hrtimer.c:1658 [inline]
 __hrtimer_run_queues+0x2db/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa5/0x100 kernel/locking/spinlock.c:194
Code: 74 05 e8 5e 8d cb f7 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4b f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> c6 15 9f f7 65 8b 05 a7 13 50 76 85 c0 74 3c 48 c7 04 24 0e 36
RSP: 0018:ffffc90005db7b40 EFLAGS: 00000206
RAX: bbd1b2827af6ba00 RBX: 0000000000000a02 RCX: bbd1b2827af6ba00
RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: 0000000000000001
RBP: ffffc90005db7bd0 R08: dffffc0000000000 R09: fffffbfff1ff7831
R10: fffffbfff1ff7831 R11: 1ffffffff1ff7830 R12: dffffc0000000000
R13: 0000000000000a02 R14: ffff8880b9143640 R15: 1ffff92000bb6f68
 spin_unlock_irqrestore include/linux/spinlock.h:418 [inline]
 srcu_might_be_idle kernel/rcu/srcutree.c:-1 [inline]
 synchronize_srcu+0xd1/0x1b0 kernel/rcu/srcutree.c:1008
 fsnotify_connector_destroy_workfn+0x40/0xa0 fs/notify/mark.c:234
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: rcu_preempt kthread starved for 10096 jiffies! g6753 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:28032 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 0
CPU: 0 PID: 4533 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:1818
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1690 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline]
RIP: 0010:smp_call_function_many_cond+0xb92/0xd70 kernel/smp.c:969
Code: 00 00 41 8b 1c 24 89 de 83 e6 01 31 ff e8 66 49 0b 00 83 e3 01 75 07 e8 fc 45 0b 00 eb 43 f3 90 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 44 05 00 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 d5
RSP: 0018:ffffc9000334f960 EFLAGS: 00000293
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: ffff888079440000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000334faa0 R08: dffffc0000000000 R09: fffffbfff1ff781f
R10: fffffbfff1ff781f R11: 1ffffffff1ff781e R12: ffff8880b91405c8
R13: 1ffff110172280b9 R14: ffff8880b903b3c0 R15: 0000000000000001
 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135
 __flush_tlb_multi arch/x86/include/asm/paravirt.h:87 [inline]
 flush_tlb_multi arch/x86/mm/tlb.c:946 [inline]
 flush_tlb_mm_range+0x360/0x560 arch/x86/mm/tlb.c:1034
 tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
 tlb_flush_mmu_tlbonly+0x1b1/0x3f0 include/asm-generic/tlb.h:430
 tlb_flush_mmu mm/mmu_gather.c:246 [inline]
 tlb_finish_mmu+0xc5/0x2e0 mm/mmu_gather.c:338
 unmap_region+0x315/0x360 mm/mmap.c:2669
 __do_munmap+0x9d3/0xdc0 mm/mmap.c:2899
 __vm_munmap+0x137/0x230 mm/mmap.c:2952
 __do_sys_munmap mm/mmap.c:2978 [inline]
 __se_sys_munmap mm/mmap.c:2974 [inline]
 __x64_sys_munmap+0x67/0x70 mm/mmap.c:2974
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f8908b7e097
Code: 73 01 c3 48 8b 0d 61 2d 0d 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 31 2d 0d 00 f7 d8 64 89 01 48
RSP: 002b:00007ffc5dd7b8e8 EFLAGS: 00000206 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 000055c1c55cbbf0 RCX: 00007f8908b7e097
RDX: 0000000000000000 RSI: 00000000009480e8 RDI: 00007f89080d0000
RBP: 000055c1c55cb910 R08: 000055c1c55de140 R09: 0000000000000006
R10: 0000000000000000 R11: 0000000000000206 R12: 000055c1875a1588
R13: 00007ffc5dd7b970 R14: 0000000000000000 R15: 0000000000000000
 </TASK>