rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (3 GPs behind) idle=343/1/0x4000000000000000 softirq=45811/45812 fqs=1 
	(t=10502 jiffies g=59505 q=375)
rcu: rcu_preempt kthread starved for 10501 jiffies! g59505 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27120 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 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 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729
NMI backtrace for cpu 0
CPU: 0 PID: 13922 Comm: syz.8.1865 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 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+0x6ea/0x1120 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+0x4ad/0xb70 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:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:___might_sleep+0x16f/0x610 kernel/sched/core.c:9626
Code: 0f b6 04 26 84 c0 0f 85 53 03 00 00 45 03 7d 00 44 3b 7c 24 2c 75 70 42 c6 44 23 0c 00 48 c7 84 24 a0 00 00 00 00 00 00 00 9c <8f> 84 24 a0 00 00 00 f7 84 24 a0 00 00 00 00 02 00 00 42 c6 44 23
RSP: 0018:ffffc9000382fb78 EFLAGS: 00000246
RAX: 0000000000000000 RBX: 1ffff92000705f78 RCX: 43e80a20fae20f00
RDX: ffff88804c790000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f780
RBP: ffffc9000382fc88 R08: ffffc9000382fe5f R09: ffffc9000382fd60
R10: dffffc0000000000 R11: fffff52000705fcc R12: dffffc0000000000
R13: ffff88804c79043c R14: 1ffff110098f2087 R15: 0000000000000000
 __might_fault+0x6b/0x110 mm/memory.c:5354
 _copy_from_user+0x29/0x170 lib/usercopy.c:14
 copy_from_user include/linux/uaccess.h:192 [inline]
 restore_sigcontext arch/x86/kernel/signal.c:91 [inline]
 __ia32_sys_rt_sigreturn+0x21d/0x760 arch/x86/kernel/signal.c:674
 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: 0033:0x7f55a5a242d9
Code: 11 06 00 66 2e 0f 1f 84 00 00 00 00 00 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 0c 25
RSP: 002b:00007ffeb6369480 EFLAGS: 00000202 ORIG_RAX: 000000000000000f
RAX: ffffffffffffffda RBX: 0000000000126027 RCX: 00007f55a5a242d9
RDX: 00007ffeb6369480 RSI: 00007ffeb63695b0 RDI: 0000000000000021
RBP: 0000000000000032 R08: 000f535adb0e1760 R09: 0000000000000000
R10: 00007ffeb6369b30 R11: 0000000000000202 R12: 00007ffeb6369b50
R13: 00007f55a5cfdfac R14: 0000000000126059 R15: 00007ffeb6369b30
 </TASK>