rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (2 ticks this GP) idle=bc7/1/0x4000000000000000 softirq=10066/10066 fqs=808 (detected by 1, t=10502 jiffies, g=12341, q=2113) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 13 Comm: kworker/0:1 Not tainted 5.15.178-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_power_efficient gc_worker RIP: 0010:match_held_lock+0x1/0xb0 kernel/locking/lockdep.c:5070 Code: 03 00 75 cf 48 c7 c7 20 2a ab 8a 48 c7 c6 60 2a ab 8a e8 f2 ca 0c f7 0f 0b eb b6 e8 09 fb ff ff 66 0f 1f 84 00 00 00 00 00 55 <53> bd 01 00 00 00 48 39 77 10 74 67 48 89 fb 81 7f 20 00 00 10 00 RSP: 0018:ffffc90000007c68 EFLAGS: 00000087 RAX: 0000000000000004 RBX: 0000000000000002 RCX: ffff88813ff20000 RDX: ffff88813ff20000 RSI: ffff88802c147b00 RDI: ffff88813ff20b40 RBP: ffff88813ff20b40 R08: ffffffff888c986b R09: 0000000000000003 R10: ffffffffffffffff R11: dffffc0000000001 R12: 0000000000000046 R13: ffff88813ff20000 R14: 00000000ffffffff R15: ffff88802c147b00 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005633cc4fb640 CR3: 000000007d364000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_is_held kernel/locking/lockdep.c:5366 [inline] lock_is_held_type+0xa4/0x180 kernel/locking/lockdep.c:5666 lock_is_held include/linux/lockdep.h:287 [inline] advance_sched+0x13d/0x940 net/sched/sch_taprio.c:721 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x598/0xcf0 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x13b/0x4b0 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_acquire+0x252/0x4f0 kernel/locking/lockdep.c:5627 Code: 2b 00 74 08 4c 89 f7 e8 9c 9e 67 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc90000d27980 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff920001a4f3c RCX: 1ffff920001a4edc RDX: dffffc0000000000 RSI: ffffffff8aab3e20 RDI: ffffffff8af9f2c0 RBP: ffffc90000d27ae0 R08: dffffc0000000000 R09: fffffbfff2131821 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff920001a4f38 R13: dffffc0000000000 R14: ffffc90000d279e0 R15: 0000000000000246 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:312 rcu_read_lock include/linux/rcupdate.h:739 [inline] gc_worker+0x289/0x14b0 net/netfilter/nf_conntrack_core.c:1470 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457 kthread+0x3f6/0x4f0 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: rcu_preempt kthread starved for 8882 jiffies! g12341 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:26816 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5027 [inline] __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373 schedule+0x11b/0x1f0 kernel/sched/core.c:6456 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x2bf/0x1080 kernel/rcu/tree.c:1972 rcu_gp_kthread+0xa4/0x360 kernel/rcu/tree.c:2145 kthread+0x3f6/0x4f0 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: 3546 Comm: udevd Not tainted 5.15.178-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1d2/0x240 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x137a/0x14d0 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3932 [inline] rcu_sched_clock_irq+0xa38/0x1150 kernel/rcu/tree.c:2619 update_process_times+0x196/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x386/0x550 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1688 [inline] __hrtimer_run_queues+0x55b/0xcf0 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x13b/0x4b0 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:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0xa93/0xd90 kernel/smp.c:969 Code: 04 03 84 c0 0f 85 84 00 00 00 45 8b 7d 00 44 89 fe 83 e6 01 31 ff e8 3c d6 0b 00 41 83 e7 01 75 07 e8 d1 d2 0b 00 eb 41 f3 90 <48> b8 00 00 00 00 00 fc ff df 0f b6 04 03 84 c0 75 11 41 f7 45 00 RSP: 0018:ffffc90002eaf720 EFLAGS: 00000293 RAX: ffffffff8174b2e4 RBX: 1ffff110171c8541 RCX: ffff88807d001dc0 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90002eaf860 R08: ffffffff8174b2b4 R09: fffffbfff2131827 R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000000 R13: ffff8880b8e42a08 R14: ffff8880b8f3b380 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:900 [inline] flush_tlb_mm_range+0x2a5/0x4a0 arch/x86/mm/tlb.c:986 dup_mmap kernel/fork.c:627 [inline] dup_mm kernel/fork.c:1466 [inline] copy_mm+0xf21/0x1370 kernel/fork.c:1518 copy_process+0x1816/0x3ef0 kernel/fork.c:2205 kernel_clone+0x210/0x960 kernel/fork.c:2603 __do_sys_clone kernel/fork.c:2720 [inline] __se_sys_clone kernel/fork.c:2704 [inline] __x64_sys_clone+0x23f/0x290 kernel/fork.c:2704 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f63697caa12 Code: 41 5d 41 5e 41 5f c3 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 10 48 8b 15 e7 43 0f 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffe0e84f4f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00005633cc4be701 RCX: 00007f63697caa12 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000000 R08: 0000000000000000 R09: 00005633cc4b6910 R10: 00007f63696b9f50 R11: 0000000000000246 R12: 00005633cc4b6500 R13: 0000000000000000 R14: 0000000000000000 R15: 00005633cc4b6910