rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (2 ticks this GP) idle=e324/1/0x4000000000000000 softirq=21449/21449 fqs=0 rcu: (detected by 0, t=10502 jiffies, g=14969, q=122 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6421 Comm: syz.0.15 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:__lock_acquire+0x29e/0xd20 kernel/locking/lockdep.c:5171 Code: 00 4c 89 6c 24 28 4a 8d 04 ad 00 00 00 00 4c 01 e8 89 f1 81 e1 ff 1f 00 00 ba 00 e0 ff ff 41 23 54 c7 20 09 ca 41 89 54 c7 20 <4d> 89 4c c7 08 49 89 5c c7 10 4c 8b 6c 24 68 4d 89 6c c7 18 65 8b RSP: 0018:ffffc90000a08b70 EFLAGS: 00000006 RAX: 000000000000000a RBX: ffff8880b8927ad8 RCX: 0000000000000071 RDX: 00000000000a4071 RSI: 0000000000000071 RDI: ffff88802e593c80 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff81ada832 R10: dffffc0000000000 R11: fffffbfff1ef9a8f R12: 0000000000000000 R13: 0000000000000002 R14: 0000000000000000 R15: ffff88802e5947b0 FS: 00007ff989d316c0(0000) GS:ffff88812623e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020001480 CR3: 0000000077e6a000 CR4: 00000000003526f0 Call Trace: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0xa2/0xf0 kernel/locking/spinlock.c:170 __run_hrtimer kernel/time/hrtimer.c:1781 [inline] __hrtimer_run_queues+0x602/0xc60 kernel/time/hrtimer.c:1841 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1903 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1058 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1052 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194 Code: 74 05 e8 5b 1c 7f f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 53 4a 47 f6 65 8b 05 dc 78 25 07 85 c0 74 40 48 c7 04 24 0e 36 RSP: 0018:ffffc9000346ee00 EFLAGS: 00000206 RAX: 7e284f8d2057dd00 RBX: 0000000000000a06 RCX: 7e284f8d2057dd00 RDX: 0000000000000002 RSI: ffffffff8d70bf53 RDI: 0000000000000001 RBP: ffffc9000346ee90 R08: ffffffff8f7cd477 R09: 1ffffffff1ef9a8e R10: dffffc0000000000 R11: fffffbfff1ef9a8f R12: dffffc0000000000 R13: dffffc0000000000 R14: ffff888026e3a2e8 R15: 1ffff9200068ddc0 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] taprio_change+0x302c/0x3c40 net/sched/sch_taprio.c:1985 taprio_init+0x959/0xbd0 net/sched/sch_taprio.c:2125 qdisc_create+0x7ac/0xea0 net/sched/sch_api.c:1319 __tc_modify_qdisc net/sched/sch_api.c:1748 [inline] tc_modify_qdisc+0x1538/0x20e0 net/sched/sch_api.c:1812 rtnetlink_rcv_msg+0x77c/0xb70 net/core/rtnetlink.c:6960 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:727 [inline] __sock_sendmsg+0x21c/0x270 net/socket.c:742 ____sys_sendmsg+0x505/0x830 net/socket.c:2630 ___sys_sendmsg+0x21f/0x2a0 net/socket.c:2684 __sys_sendmsg net/socket.c:2716 [inline] __do_sys_sendmsg net/socket.c:2721 [inline] __se_sys_sendmsg net/socket.c:2719 [inline] __x64_sys_sendmsg+0x19b/0x260 net/socket.c:2719 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff988f7e719 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:00007ff989d31038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ff989135f80 RCX: 00007ff988f7e719 RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000004 RBP: 00007ff988ff139e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ff989135f80 R15: 00007fff64931ff8 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g14969 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=4666 rcu: rcu_preempt kthread starved for 10502 jiffies! g14969 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:27288 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 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+0x4bc/0x870 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245