rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (0 ticks this GP) idle=ea44/1/0x4000000000000000 softirq=16865/16865 fqs=0 rcu: (detected by 0, t=10506 jiffies, g=12149, q=251 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 43 Comm: kworker/1:1 Not tainted 6.15.0-syzkaller-12426-ge271ed52b344 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_power_efficient gc_worker RIP: 0010:__this_cpu_preempt_check+0x0/0x20 lib/smp_processor_id.c:65 Code: 86 16 cd f5 eb a7 e8 bf e4 ff ff 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 89 fe 48 c7 c7 40 83 e2 8b e9 bd fe ff ff cc cc cc RSP: 0018:ffffc90000a08c20 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 170f93910d12aa00 RDX: ffff8880206cbc00 RSI: ffff888031238300 RDI: ffffffff8db6970d RBP: 00000000ffffffff R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200014117c R12: 0000000000000046 R13: ffff8880206cbc00 R14: ffff888031238300 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff888125d55000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7f33a60d58 CR3: 00000000785a3000 CR4: 0000000000350ef0 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:473 [inline] lock_is_held_type+0xfe/0x190 kernel/locking/lockdep.c:5944 lock_is_held include/linux/lockdep.h:249 [inline] advance_sched+0x1d2/0xc90 net/sched/sch_taprio.c:929 __run_hrtimer kernel/time/hrtimer.c:1761 [inline] __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_is_held_type+0x14d/0x190 kernel/locking/lockdep.c:5948 Code: 75 4c 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 05 09 f3 36 07 48 3b 44 24 08 75 43 89 d8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f <5d> e9 d8 83 aa f5 cc 90 0f 0b 90 48 c7 c7 47 cc 97 8d e8 fc 15 00 RSP: 0018:ffffc90000b372b0 EFLAGS: 00000286 RAX: 0000000000000000 RBX: ffffc90000b30000 RCX: 170f93910d12aa00 RDX: 0000000000000000 RSI: ffffffff8db6970d RDI: ffffffff8be28340 RBP: 00000000ffffffff R08: ffffffff8fa101f7 R09: 1ffffffff1f4203e R10: dffffc0000000000 R11: fffffbfff1f4203f R12: ffff8880b873c408 R13: dffffc0000000000 R14: ffff8880206cbc00 R15: ffff888125d55000 lock_is_held include/linux/lockdep.h:249 [inline] schedule_debug kernel/sched/core.c:5982 [inline] __schedule+0x274/0x4d00 kernel/sched/core.c:6682 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6965 preempt_schedule+0xae/0xc0 kernel/sched/core.c:6989 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xfd/0x110 kernel/locking/spinlock.c:194 rcu_report_exp_rnp kernel/rcu/tree_exp.h:225 [inline] rcu_preempt_deferred_qs_irqrestore+0x874/0xc40 kernel/rcu/tree_plugin.h:579 rcu_read_unlock_special+0x3fe/0x4c0 kernel/rcu/tree_plugin.h:693 __rcu_read_unlock+0x84/0xe0 kernel/rcu/tree_plugin.h:438 rcu_read_unlock include/linux/rcupdate.h:873 [inline] gc_worker+0xbab/0x1380 net/netfilter/nf_conntrack_core.c:1606 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g12149 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=5117 rcu: rcu_preempt kthread starved for 10506 jiffies! g12149 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27320 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245