rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 ticks this GP) idle=bcb/1/0x4000000000000000 softirq=9873/9873 fqs=1238 (detected by 0, t=10502 jiffies, g=12205, q=1121) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 4238 Comm: kworker/1:3 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: events_power_efficient gc_worker RIP: 0010:lock_is_held_type+0x1c/0x190 kernel/locking/lockdep.c:5651 Code: bf e8 98 fd ff ff 0f 1f 84 00 00 00 00 00 55 41 57 41 56 41 55 41 54 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 ff ff ff ff 83 3d 1c d1 c0 03 00 0f 84 03 01 00 00 65 8b 05 8b RSP: 0018:ffffc90000dd0c38 EFLAGS: 00000082 RAX: ca010fb9e2499600 RBX: 0000000000000001 RCX: ffff888078438000 RDX: 0000000000010000 RSI: 00000000ffffffff RDI: ffff88807e36b300 RBP: ffff88807e36b340 R08: 0000000000000004 R09: 0000000000000003 R10: fffff520001ba180 R11: 1ffff920001ba180 R12: ffff88807e36b000 R13: dffffc0000000000 R14: ffff88805768ff80 R15: ffff88802b908700 FS: 0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000600 CR3: 0000000057a21000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_is_held include/linux/lockdep.h:287 [inline] advance_sched+0x141/0x940 net/sched/sch_taprio.c:721 __run_hrtimer kernel/time/hrtimer.c:1690 [inline] __hrtimer_run_queues+0x53d/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:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5671 Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc9000344f978 EFLAGS: 00000206 RAX: ca010fb9e2499600 RBX: ffff888078438000 RCX: ca010fb9e2499600 RDX: 0000000000000000 RSI: ffffffff8a0b28c0 RDI: ffffffff8a59a240 RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff1ad31be R10: fffffbfff1ad31be R11: 1ffffffff1ad31bd R12: 0000000000000002 R13: 0000000000000246 R14: ffffffff8c11c4c0 R15: ffff888078438b40 lock_is_held include/linux/lockdep.h:287 [inline] ___might_sleep+0xa3/0x600 kernel/sched/core.c:9624 gc_worker+0xc52/0x13a0 net/netfilter/nf_conntrack_core.c:1544 process_one_work+0x863/0x1000 kernel/workqueue.c:2310 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: rcu_preempt kthread starved for 8024 jiffies! g12205 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: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: 4882 Comm: syz.0.16 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_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:rep_nop arch/x86/include/asm/vdso/processor.h:13 [inline] RIP: 0010:cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0xb86/0xd70 kernel/smp.c:969 Code: 41 0f b6 44 05 00 84 c0 0f 85 9d 00 00 00 41 8b 1c 24 89 de 83 e6 01 31 ff e8 66 49 0b 00 83 e3 01 75 07 e8 fc 45 0b 00 eb 43 90 48 b8 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 75 11 RSP: 0018:ffffc9000352f4e0 EFLAGS: 00000293 RAX: ffffffff816c84db RBX: 0000000000000001 RCX: ffff88805c781dc0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000352f620 R08: dffffc0000000000 R09: fffffbfff183bf68 R10: fffffbfff183bf68 R11: 1ffffffff183bf67 R12: ffff8880b9140588 R13: 1ffff110172280b1 R14: ffff8880b903b380 R15: 0000000000000001 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135 __flush_tlb_multi arch/x86/include/asm/paravirt.h:87 [inline] flush_tlb_multi arch/x86/mm/tlb.c:946 [inline] flush_tlb_mm_range+0x360/0x560 arch/x86/mm/tlb.c:1034 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly+0x1b1/0x3f0 include/asm-generic/tlb.h:430 tlb_flush_mmu mm/mmu_gather.c:246 [inline] tlb_finish_mmu+0xc5/0x2e0 mm/mmu_gather.c:338 exit_mmap+0x3a6/0x5f0 mm/mmap.c:3218 __mmput+0x115/0x3b0 kernel/fork.c:1127 exit_mm+0x567/0x6c0 kernel/exit.c:550 do_exit+0x5a1/0x20a0 kernel/exit.c:870 do_group_exit+0x12e/0x300 kernel/exit.c:997 get_signal+0x6ca/0x12c0 kernel/signal.c:2900 arch_do_signal_or_restart+0xc1/0x1300 arch/x86/kernel/signal.c:867 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+0xb1/0x140 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: 0033:0x7f0323966929 Code: Unable to access opcode bytes at RIP 0x7f03239668ff. RSP: 002b:00007f0322bd6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: 00000000000000c4 RBX: 00007f0323b8dfa0 RCX: 00007f0323966929 RDX: 0000000000000000 RSI: 00002000000007c0 RDI: 0000000000000004 RBP: 00007f03239e8b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f0323b8dfa0 R15: 00007ffdf461b428