rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (4 ticks this GP) idle=5a5/1/0x4000000000000002 softirq=20763/20764 fqs=54 (detected by 1, t=10505 jiffies, g=27121, q=188) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 9039 Comm: syz.6.1334 Not tainted 5.15.189-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:check_preemption_disabled+0x47/0x110 lib/smp_processor_id.c:55 Code: 59 76 65 8b 0d 12 32 5a 76 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00 00 00 48 3b 4c 24 08 0f 85 c4 00 00 00 48 83 c4 10 5b <41> 5e 41 5f 5d c3 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 RSP: 0018:ffffc90000007440 EFLAGS: 00000082 RAX: 0000000000000000 RBX: ffff8880620d11e8 RCX: 076f2218aac86f00 RDX: 0000000000000100 RSI: ffffffff8a599320 RDI: ffffffff8a5992e0 RBP: ffffc90000007590 R08: dffffc0000000000 R09: fffffbfff1ff6e19 R10: fffffbfff1ff6e19 R11: 1ffffffff1ff6e18 R12: 0000000000000001 R13: 1ffff92000000e94 R14: ffffc90000007520 R15: ffffc90000007680 FS: 00007fe9b794b6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000100000000 CR3: 000000001f50d000 CR4: 00000000003506f0 DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:331 [inline] rcu_is_watching+0x11/0xa0 kernel/rcu/tree.c:1123 rcu_read_lock include/linux/rcupdate.h:740 [inline] __perf_event_output kernel/events/core.c:7786 [inline] perf_event_output_forward+0xb9/0x280 kernel/events/core.c:7808 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9501 perf_tp_event+0x32c/0xb50 kernel/events/core.c:10033 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10007 perf_trace_preemptirq_template+0x2be/0x380 include/trace/events/preemptirq.h:14 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713 RIP: 0010:rcu_read_unlock_special+0x84/0x480 kernel/rcu/tree_plugin.h:671 Code: f1 f1 f1 00 f2 f2 f2 4a 89 04 2b 66 42 c7 44 2b 09 f3 f3 42 c6 44 2b 0b f3 65 44 8b 35 7d 16 9e 7e 41 f7 c6 00 00 f0 00 74 45 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 66 42 c7 44 2b RSP: 0018:ffffc90000007ae0 EFLAGS: 00000206 RAX: 076f2218aac86f00 RBX: 1ffff92000000f60 RCX: 076f2218aac86f00 RDX: dffffc0000000000 RSI: ffffffff8a0b15c0 RDI: ffffffff8a599340 RBP: ffffc90000007bb8 R08: dffffc0000000000 R09: fffffbfff1ff6e36 R10: fffffbfff1ff6e36 R11: 1ffffffff1ff6e35 R12: ffffffff8c120800 R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422 rcu_read_unlock include/linux/rcupdate.h:771 [inline] ieee80211_iterate_active_interfaces_atomic+0x132/0x140 net/mac80211/util.c:831 mac80211_hwsim_beacon+0x9b/0x180 drivers/net/wireless/mac80211_hwsim.c:1865 __run_hrtimer kernel/time/hrtimer.c:1690 [inline] __hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1754 hrtimer_run_softirq+0x176/0x240 kernel/time/hrtimer.c:1771 handle_softirqs+0x328/0x820 kernel/softirq.c:576 __do_softirq kernel/softirq.c:610 [inline] invoke_softirq kernel/softirq.c:450 [inline] __irq_exit_rcu+0x12f/0x220 kernel/softirq.c:659 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:__refcount_add include/linux/refcount.h:198 [inline] RIP: 0010:__refcount_inc include/linux/refcount.h:250 [inline] RIP: 0010:refcount_inc include/linux/refcount.h:267 [inline] RIP: 0010:get_task_struct include/linux/sched/task.h:107 [inline] RIP: 0010:mark_wake_futex+0xba/0x150 kernel/futex/core.c:1542 Code: ef 4f 00 49 83 3c 24 00 0f 85 80 00 00 00 4d 8d 67 28 4c 89 e7 be 04 00 00 00 e8 11 f1 4f 00 bd 01 00 00 00 f0 41 0f c1 6f 28 <31> ff 89 ee e8 7d 8f 0b 00 85 ed 74 61 bf fe ff ff 7f 89 ee e8 6d RSP: 0018:ffffc9000137fb68 EFLAGS: 00000202 RAX: 1ffff920005c3f01 RBX: ffffc9000137fc20 RCX: ffffffff816c37ef RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffff888020953ba8 RBP: 0000000000000001 R08: dffffc0000000000 R09: ffffed100412a776 R10: ffffed100412a776 R11: 1ffff1100412a775 R12: ffff888020953ba8 R13: dffffc0000000000 R14: ffffc90002e1fbb0 R15: ffff888020953b80 futex_wake+0x3a6/0x530 kernel/futex/core.c:1695 do_futex+0xcde/0x1240 kernel/futex/core.c:3987 __do_sys_futex kernel/futex/core.c:4059 [inline] __se_sys_futex+0x3a3/0x430 kernel/futex/core.c:4040 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: 0033:0x7fe9b96e3be9 Code: 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 01 48 RSP: 002b:00007fe9b794b0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007fe9b990afa8 RCX: 00007fe9b96e3be9 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fe9b990afac RBP: 00007fe9b990afa0 R08: 002ae497813d9dde R09: 0000000000000000 R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe9b990b038 R14: 00007ffdd373e6e0 R15: 00007ffdd373e7c8 rcu: rcu_preempt kthread starved for 10235 jiffies! g27121 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:27656 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5030 [inline] __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376 schedule+0x11b/0x1e0 kernel/sched/core.c:6459 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: 9036 Comm: syz.6.1334 Not tainted 5.15.189-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_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 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] RIP: 0010:kvm_wait+0x141/0x190 arch/x86/kernel/kvm.c:918 Code: 89 df 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 47 0f b6 1f e8 5f da 49 00 44 38 e3 75 10 66 90 0f 00 2d 61 63 d4 08 fb f4 33 ff ff ff fb e9 2d ff ff ff e8 7f 25 74 08 89 f9 80 e1 07 38 RSP: 0018:ffffc90002e1f840 EFLAGS: 00000246 RAX: 0375caed294cd200 RBX: 0000000000000003 RCX: 0375caed294cd200 RDX: dffffc0000000000 RSI: ffffffff8a0b15c0 RDI: ffffffff8a599340 RBP: ffffc90002e1f8f0 R08: dffffc0000000000 R09: fffffbfff1ff6e36 R10: fffffbfff1ff6e36 R11: 1ffffffff1ff6e35 R12: 0000000000000003 R13: ffff8880b913b114 R14: dffffc0000000000 R15: 1ffff920005c3f08 pv_wait arch/x86/include/asm/paravirt.h:597 [inline] pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline] __pv_queued_spin_lock_slowpath+0x60f/0x9c0 kernel/locking/qspinlock.c:508 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline] queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline] do_raw_spin_lock+0x217/0x280 kernel/locking/spinlock_debug.c:115 spin_lock include/linux/spinlock.h:363 [inline] unqueue_me kernel/futex/core.c:2548 [inline] futex_wait+0x21b/0x5c0 kernel/futex/core.c:2968 do_futex+0xd1c/0x1240 kernel/futex/core.c:3982 __do_sys_futex kernel/futex/core.c:4059 [inline] __se_sys_futex+0x3a3/0x430 kernel/futex/core.c:4040 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: 0033:0x7fe9b96e3be9 Code: 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 01 48 RSP: 002b:00007ffdd373e928 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 0000000000030c27 RCX: 00007fe9b96e3be9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe9b990afac RBP: 0000000000000032 R08: 002a4c01010e3a18 R09: 00000006d373ec1f R10: 00007ffdd373ea20 R11: 0000000000000246 R12: 00007fe9b990afac R13: 00007ffdd373ea20 R14: 0000000000030c59 R15: 00007ffdd373ea40