hrtimer: interrupt took 92308 ns rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P3561/1:b..l (detected by 1, t=10502 jiffies, g=12453, q=137) task:udevd state:R running task stack:22816 pid: 3561 ppid: 1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0xf6/0x100 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:419 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x11b/0x180 kernel/sched/wait.c:205 sock_def_readable+0x136/0x250 net/core/sock.c:3098 __netlink_sendskb net/netlink/af_netlink.c:1264 [inline] netlink_sendskb+0x97/0x130 net/netlink/af_netlink.c:1270 netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2446 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2500 __sys_sendmsg net/socket.c:2529 [inline] __do_sys_sendmsg net/socket.c:2538 [inline] __se_sys_sendmsg+0x190/0x250 net/socket.c:2536 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: 0033:0x7fb279c01407 RSP: 002b:00007ffd2525b9f0 EFLAGS: 00000202 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fb279b13880 RCX: 00007fb279c01407 RDX: 0000000000000000 RSI: 00007ffd2525ba50 RDI: 0000000000000004 RBP: 0000559ba84b6790 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00000000000000b4 R13: 0000559ba840b9e0 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10511 jiffies! g12453 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:27808 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 1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 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_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: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 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:sched_core_balance+0x124/0xbb0 kernel/sched/core.c:6076 Code: 48 c7 c2 00 bf 0a 8a e8 9a 7c 4c 08 4c 89 74 24 18 e9 19 0a 00 00 48 8b 7c 24 20 e8 46 92 60 08 e8 e1 a0 2b 00 fb 41 83 fe 08 <0f> 83 e6 09 00 00 48 8b 44 24 40 4c 8d 24 c5 20 c8 bc 8b 4c 89 e0 RSP: 0018:ffffc90000d67960 EFLAGS: 00000297 RAX: 7dccb3226d7d7d00 RBX: ffff8880b913b088 RCX: 7dccb3226d7d7d00 RDX: dffffc0000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580 RBP: ffffc90000d67ab0 R08: dffffc0000000000 R09: ffffed1017207469 R10: ffffed1017207469 R11: 1ffff11017207468 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000001 R15: dffffc0000000000 do_balance_callbacks kernel/sched/core.c:4692 [inline] __balance_callbacks kernel/sched/core.c:4746 [inline] finish_lock_switch+0x17b/0x280 kernel/sched/core.c:4802 finish_task_switch+0x12f/0x640 kernel/sched/core.c:4921 context_switch kernel/sched/core.c:5052 [inline] __schedule+0x11c3/0x4390 kernel/sched/core.c:6395 schedule_idle+0x4a/0x90 kernel/sched/core.c:6506 do_idle+0x556/0x5b0 kernel/sched/idle.c:334 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:403 start_secondary+0x31f/0x430 arch/x86/kernel/smpboot.c:281 secondary_startup_64_no_verify+0xb1/0xbb vkms_vblank_simulate: vblank timer overrun