rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10499 ticks this GP) idle=d9d/1/0x4000000000000000 softirq=24257/24257 fqs=8 
	(t=10500 jiffies g=29473 q=138)
rcu: rcu_preempt kthread starved for 10482 jiffies! g29473 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:27496 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7788 Comm: syz.3.1052 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:hlock_class kernel/locking/lockdep.c:197 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3700 [inline]
RIP: 0010:validate_chain kernel/locking/lockdep.c:3756 [inline]
RIP: 0010:__lock_acquire+0x13bf/0x7c60 kernel/locking/lockdep.c:5012
Code: e8 03 25 f8 03 00 00 48 8d b8 c0 e0 fb 8f be 08 00 00 00 e8 f3 22 60 00 49 b8 00 00 00 00 00 fc ff df 48 0f a3 1d e1 cd 9f 0e <72> 25 48 c7 c0 80 4f 0c 96 48 c1 e8 03 42 0f b6 04 00 84 c0 0f 85
RSP: 0018:ffffc90003adf880 EFLAGS: 00000057
RAX: 0000000000000001 RBX: 000000000000019b RCX: ffffffff815c12cd
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ffbe0f0
RBP: ffffc90003adfad0 R08: dffffc0000000000 R09: fffffbfff1ff7c1f
R10: fffffbfff1ff7c1f R11: 1ffffffff1ff7c1e R12: c43e8954cd7f2d9e
R13: ffff88802b4d9dc0 R14: 00000000cd7f2d9e R15: ffff88802b4da8d0
FS:  00007f196a5466c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 000000007e353000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
 __might_fault+0xb3/0x110 mm/memory.c:5357
 _copy_to_user+0x29/0x130 lib/usercopy.c:35
 copy_to_user include/linux/uaccess.h:200 [inline]
 copy_siginfo_to_user+0x20/0x80 kernel/signal.c:3367
 __setup_rt_frame arch/x86/kernel/signal.c:490 [inline]
 setup_rt_frame arch/x86/kernel/signal.c:780 [inline]
 handle_signal arch/x86/kernel/signal.c:824 [inline]
 arch_do_signal_or_restart+0xd56/0x1300 arch/x86/kernel/signal.c:869
 handle_signal_work kernel/entry/common.c:154 [inline]
 exit_to_user_mode_loop+0x9e/0x130 kernel/entry/common.c:178
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f196c2df747
Code: ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89
RSP: 002b:00007f196a5460e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007f196c535fa8 RCX: 00007f196c2df749
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f196c535fa8
RBP: 00007f196c535fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f196c536038 R14: 00007ffcbc6d2aa0 R15: 00007ffcbc6d2b88
 </TASK>
NMI backtrace for cpu 1
CPU: 1 PID: 7782 Comm: syz.0.1050 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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_dump_cpu_stacks+0x22f/0x380 kernel/rcu/tree_stall.h:349
 print_cpu_stall+0x31d/0x5f0 kernel/rcu/tree_stall.h:633
 check_cpu_stall kernel/rcu/tree_stall.h:727 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x6d8/0x1110 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:1685 [inline]
 __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 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_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202
Code: f6 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 de 9e a9 f7 48 89 df e8 a6 73 aa f7 e8 41 0d cb f7 fb bf 01 00 00 00 <e8> 76 95 9e f7 65 8b 05 07 93 4f 76 85 c0 74 02 5b c3 e8 b4 9d 4d
RSP: 0018:ffffc900034dfcf0 EFLAGS: 00000286
RAX: f53a45ebbf325500 RBX: ffff8880579640c0 RCX: f53a45ebbf325500
RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: 0000000000000001
RBP: ffffc900034dff10 R08: dffffc0000000000 R09: ffffed100af2c819
R10: ffffed100af2c819 R11: 1ffff1100af2c818 R12: ffff88807df1bb80
R13: 1ffff9200069bffe R14: 1ffff9200069bfa8 R15: ffffc900034dfff0
 __ia32_sys_rt_sigreturn+0x184/0x790 arch/x86/kernel/signal.c:672
 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: 0033:0x7f4740a6a829
Code: 64 c7 00 16 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 04 25
RSP: 002b:00007ffc69329ec0 EFLAGS: 00000202 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 0000000000052d42 RCX: 00007f4740a6a829
RDX: 00007ffc69329ec0 RSI: 00007ffc69329ff0 RDI: 0000000000000021
RBP: 0000000000000fd2 R08: 000fc154d81909dc R09: 000000146932a74f
R10: 00007ffc6932a550 R11: 0000000000000202 R12: 00007f4740d24fac
R13: 00007ffc6932a550 R14: 0000000000053d14 R15: 00007ffc6932a570
 </TASK>