rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=bbfc/1/0x4000000000000000 softirq=14781/14781 fqs=0 rcu: (detected by 1, t=10502 jiffies, g=11189, q=106 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 20 Comm: rcu_exp_gp_kthr Not tainted 6.14.0-rc7-syzkaller-00137-g5fc319360819 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:469 [inline] RIP: 0010:lock_is_held_type+0xf5/0x190 kernel/locking/lockdep.c:5924 Code: ee e8 cf 5a 25 f9 eb cb 31 db eb 1e 41 83 fe ff 74 13 31 c0 f6 43 22 03 0f 95 c0 31 db 44 39 f0 0f 94 c3 eb 05 bb 01 00 00 00 <48> c7 c7 00 c6 2a 8c e8 7f 1a 00 00 b8 ff ff ff ff 65 0f c1 05 62 RSP: 0018:ffffc90000007c28 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffff88801d69da00 RDX: ffff88801d69da00 RSI: ffff888027cac300 RDI: ffff88801d69e4f0 RBP: 0000000000000000 R08: ffffffff8a05262b R09: fffff52000000f7c R10: dffffc0000000000 R11: fffff52000000f7c R12: 0000000000000046 R13: ffff88801d69da00 R14: 00000000ffffffff R15: ffff888027cac300 FS: 0000000000000000(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000600 CR3: 000000002f914000 CR4: 0000000000350ef0 Call Trace: lock_is_held include/linux/lockdep.h:249 [inline] advance_sched+0xcd/0xca0 net/sched/sch_taprio.c:925 __run_hrtimer kernel/time/hrtimer.c:1801 [inline] __hrtimer_run_queues+0x59d/0xd30 kernel/time/hrtimer.c:1865 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1927 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x112/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194 Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 4e 59 1d f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 b3 bc 83 f5 65 8b 05 a4 0f f8 73 85 c0 74 43 48 c7 04 24 0e 36 RSP: 0018:ffffc90000197820 EFLAGS: 00000206 RAX: 85548c2d7975cc00 RBX: 1ffff92000032f08 RCX: ffffffff9a654903 RDX: dffffc0000000000 RSI: ffffffff8c2ab3a0 RDI: 0000000000000001 RBP: ffffc900001978b0 R08: ffffffff903cfb77 R09: 1ffffffff2079f6e R10: dffffc0000000000 R11: fffffbfff2079f6f R12: dffffc0000000000 R13: 1ffff92000032f04 R14: ffffc90000197840 R15: 0000000000000246 debug_object_assert_init+0x2dd/0x4b0 lib/debugobjects.c:1009 debug_timer_assert_init kernel/time/timer.c:845 [inline] debug_assert_init kernel/time/timer.c:890 [inline] __try_to_del_timer_sync+0x29/0x390 kernel/time/timer.c:1499 __timer_delete_sync+0x245/0x310 kernel/time/timer.c:1662 del_timer_sync include/linux/timer.h:185 [inline] schedule_timeout+0x162/0x290 kernel/time/sleep_timeout.c:100 synchronize_rcu_expedited_wait_once kernel/rcu/tree_exp.h:543 [inline] synchronize_rcu_expedited_wait kernel/rcu/tree_exp.h:656 [inline] rcu_exp_wait_wake kernel/rcu/tree_exp.h:685 [inline] rcu_exp_sel_wait_wake+0x779/0x1dc0 kernel/rcu/tree_exp.h:719 kthread_worker_fn+0x4f9/0xb70 kernel/kthread.c:1010 kthread+0x7ab/0x920 kernel/kthread.c:464 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g11189 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=3110 rcu: rcu_preempt kthread starved for 10502 jiffies! g11189 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26104 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x190e/0x4c90 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226 kthread+0x7ab/0x920 kernel/kthread.c:464 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244