rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10500 ticks this GP) idle=5cb/1/0x4000000000000000 softirq=7376/7376 fqs=0 (t=10501 jiffies g=7613 q=2116) rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g7613 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=3395 rcu: rcu_preempt kthread starved for 10504 jiffies! g7613 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:28032 pid: 15 ppid: 2 flags:0x00004000 Call Trace: 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 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 0 CPU: 0 PID: 4429 Comm: syz.1.24 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: 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_cpu_stall+0x318/0x5f0 kernel/rcu/tree_stall.h:631 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: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 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 3e 1d aa f7 48 89 df e8 06 f2 aa f7 e8 c1 8c cb f7 fb bf 01 00 00 00 46 15 9f f7 65 8b 05 27 13 50 76 85 c0 74 02 5b c3 e8 d4 1d 4e RSP: 0018:ffffc9000340fb50 EFLAGS: 00000282 RAX: d223fd4e3d900200 RBX: ffff88802a47c0c0 RCX: d223fd4e3d900200 RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: 0000000000000001 RBP: ffffc9000340fcb0 R08: dffffc0000000000 R09: ffffed100548f819 R10: ffffed100548f819 R11: 1ffff1100548f818 R12: dffffc0000000000 R13: 0000000100000000 R14: 0000000000000000 R15: 0000000000000020 set_current_blocked kernel/signal.c:3072 [inline] signal_delivered kernel/signal.c:2936 [inline] signal_setup_done+0x28c/0x440 kernel/signal.c:2947 handle_signal arch/x86/kernel/signal.c:842 [inline] arch_do_signal_or_restart+0xf2e/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: 0033:0x7fcc6f03d2e0 Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d 6a 3e 08 00 e8 25 90 f8 ff 0f 1f 44 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <83> ff 21 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 f3 48 RSP: 002b:00007fffce4f2bf8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007fcc6f25bfa0 RCX: 00007fcc6f014ba9 RDX: 00007fffce4f2c00 RSI: 00007fffce4f2d30 RDI: 0000000000000021 RBP: 00007fcc6f097e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcc6f25bfa0 R14: 00007fcc6f25bfa0 R15: 0000000000000004 NMI backtrace for cpu 0 CPU: 0 PID: 4429 Comm: syz.1.24 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: 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: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 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 3e 1d aa f7 48 89 df e8 06 f2 aa f7 e8 c1 8c cb f7 fb bf 01 00 00 00 46 15 9f f7 65 8b 05 27 13 50 76 85 c0 74 02 5b c3 e8 d4 1d 4e RSP: 0018:ffffc9000340fb50 EFLAGS: 00000282 RAX: d223fd4e3d900200 RBX: ffff88802a47c0c0 RCX: d223fd4e3d900200 RDX: dffffc0000000000 RSI: ffffffff8a0b1820 RDI: 0000000000000001 RBP: ffffc9000340fcb0 R08: dffffc0000000000 R09: ffffed100548f819 R10: ffffed100548f819 R11: 1ffff1100548f818 R12: dffffc0000000000 R13: 0000000100000000 R14: 0000000000000000 R15: 0000000000000020 set_current_blocked kernel/signal.c:3072 [inline] signal_delivered kernel/signal.c:2936 [inline] signal_setup_done+0x28c/0x440 kernel/signal.c:2947 handle_signal arch/x86/kernel/signal.c:842 [inline] arch_do_signal_or_restart+0xf2e/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: 0033:0x7fcc6f03d2e0 Code: 83 c0 16 83 e0 f7 74 12 50 48 8d 3d 6a 3e 08 00 e8 25 90 f8 ff 0f 1f 44 00 00 c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <83> ff 21 74 0b c3 66 2e 0f 1f 84 00 00 00 00 00 55 53 48 89 f3 48 RSP: 002b:00007fffce4f2bf8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 00007fcc6f25bfa0 RCX: 00007fcc6f014ba9 RDX: 00007fffce4f2c00 RSI: 00007fffce4f2d30 RDI: 0000000000000021 RBP: 00007fcc6f097e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcc6f25bfa0 R14: 00007fcc6f25bfa0 R15: 0000000000000004 sched: RT throttling activated