rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 ticks this GP) idle=a37c/1/0x4000000000000000 softirq=19069/19069 fqs=0 rcu: (detected by 1, t=10502 jiffies, g=13481, q=260 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6141 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:separate_irq_context kernel/locking/lockdep.c:4703 [inline] RIP: 0010:__lock_acquire+0x73c/0xd20 kernel/locking/lockdep.c:5221 Code: 00 00 83 fb 31 0f 83 e0 05 00 00 48 8d 04 9b 45 8b 66 20 48 8b 4c 24 10 8b 44 c1 f8 44 31 e0 25 00 60 00 00 31 c9 89 c2 f7 da <48> 19 c9 49 09 cf 85 c0 b8 01 00 00 00 0f 45 e8 eb 4b 48 89 fb 4c RSP: 0018:ffffc90000007ad0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff888076c32940 RDI: ffff888076c31e00 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff84d0bb8a R10: dffffc0000000000 R11: fffff52000000f98 R12: 00000000000c4000 R13: 0000000000000002 R14: ffff888076c32940 R15: bc101d9a73125dae FS: 00007fe6e98f06c0(0000) GS:ffff888125c13000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f79bef0ea90 CR3: 00000000713fd000 CR4: 0000000000350ef0 Call Trace: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 debug_object_deactivate+0x9a/0x250 lib/debugobjects.c:873 debug_hrtimer_deactivate kernel/time/hrtimer.c:450 [inline] debug_deactivate+0x1d/0x200 kernel/time/hrtimer.c:490 __run_hrtimer kernel/time/hrtimer.c:1729 [inline] __hrtimer_run_queues+0x2b0/0xc60 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:lockdep_unregister_key+0x2c5/0x310 kernel/locking/lockdep.c:6616 Code: 65 48 8b 05 4d 4d 03 11 48 3b 44 24 10 0f 84 26 fe ff ff e8 0d d4 dc 09 e8 38 d5 dc 09 41 f7 c7 00 02 00 00 74 bd fb 40 84 ed <75> bc eb cd 90 0f 0b 90 e9 19 ff ff ff 90 0f 0b 90 e9 2a ff ff ff RSP: 0018:ffffc9000384f088 EFLAGS: 00000246 RAX: 3f005e3c0a9bf500 RBX: ffff88807ea64298 RCX: 3f005e3c0a9bf500 RDX: ffffffff93649338 RSI: ffffffff8d9cdeec RDI: ffffffff8be33f80 RBP: ffff88807ea64200 R08: 0000000000000000 R09: ffffffff81aa8548 R10: dffffc0000000000 R11: fffffbfff1f474e7 R12: 0000000000000000 R13: 0000000000001000 R14: 0000000000000001 R15: 0000000000000213 __qdisc_destroy+0x166/0x420 net/sched/sch_generic.c:1083 taprio_attach+0x25a/0x380 net/sched/sch_taprio.c:2160 qdisc_graft+0x1175/0x1590 net/sched/sch_api.c:1162 __tc_modify_qdisc net/sched/sch_api.c:1756 [inline] tc_modify_qdisc+0x189b/0x20e0 net/sched/sch_api.c:1812 rtnetlink_rcv_msg+0x77c/0xb70 net/core/rtnetlink.c:6955 netlink_rcv_skb+0x208/0x470 net/netlink/af_netlink.c:2552 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x82f/0x9e0 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x805/0xb30 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:714 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:729 ____sys_sendmsg+0x505/0x830 net/socket.c:2614 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2668 __sys_sendmsg net/socket.c:2700 [inline] __do_sys_sendmsg net/socket.c:2705 [inline] __se_sys_sendmsg net/socket.c:2703 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2703 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe6e898ec29 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:00007fe6e98f0038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fe6e8bd5fa0 RCX: 00007fe6e898ec29 RDX: 0000000000000000 RSI: 00002000000007c0 RDI: 0000000000000004 RBP: 00007fe6e8a11e41 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe6e8bd6038 R14: 00007fe6e8bd5fa0 R15: 00007ffd575cfbe8 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g13481 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=4468 rcu: rcu_preempt kthread starved for 10502 jiffies! g13481 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:27160 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x439/0x7d0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245