rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=2f2c/1/0x4000000000000000 softirq=19109/19110 fqs=0 rcu: (detected by 1, t=10505 jiffies, g=10189, q=1330 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6229 Comm: syz-executor.0 Not tainted 6.16.0-rc4-syzkaller-g1f988d0788f5 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:158 [inline] RIP: 0010:lock_is_held_type+0xf8/0x150 kernel/locking/lockdep.c:5945 Code: f0 41 0f 94 c5 48 c7 c7 7b c2 e0 8d e8 f1 13 00 00 b8 ff ff ff ff 65 0f c1 05 9c b0 48 08 83 f8 01 75 2d 9c 58 f6 c4 02 75 43 <48> f7 04 24 00 02 00 00 74 01 fb 48 83 c4 08 44 89 e8 5b 5d 41 5c RSP: 0018:ffffc90000007e00 EFLAGS: 00000046 RAX: 0000000000000046 RBX: ffff888023378b18 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8de0c27b RDI: ffffffff8c1588a0 RBP: ffff8880b8427c98 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: ffffffff9afe38c8 R12: ffff888023378000 R13: 0000000000000001 R14: 00000000ffffffff R15: 0000000000000001 FS: 00007fd5297016c0(0000) GS:ffff888124715000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd527dfed58 CR3: 000000005250a000 CR4: 00000000003526f0 Call Trace: lock_is_held include/linux/lockdep.h:249 [inline] __run_hrtimer kernel/time/hrtimer.c:1727 [inline] __hrtimer_run_queues+0x86a/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x108/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/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+0xe9/0x140 kernel/locking/lockdep.c:6619 Code: 48 89 ef e8 b9 e5 ff ff 48 83 2d 89 5d 58 14 01 89 c3 e8 da ee ff ff 9c 58 f6 c4 02 75 52 41 f7 c4 00 02 00 00 74 01 fb 84 db <75> 1b 5b 5d 41 5c e9 4c 74 0a 00 8b 05 3a 8c 11 0f 31 db 85 c0 74 RSP: 0018:ffffc90004cf7340 EFLAGS: 00000246 RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8df24703 RDI: ffffffff8c1588a0 RBP: ffffffff97557a38 R08: 000000000000dde2 R09: ffffffff95f235a4 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000246 R13: ffff88802be64000 R14: ffff88805147c000 R15: ffff88802be64000 __qdisc_destroy+0x11a/0x4d0 net/sched/sch_generic.c:1081 qdisc_put+0xab/0xe0 net/sched/sch_generic.c:1107 taprio_attach+0x1fc/0x370 net/sched/sch_taprio.c:2149 qdisc_graft+0xe3c/0x17c0 net/sched/sch_api.c:1167 __tc_modify_qdisc net/sched/sch_api.c:1757 [inline] tc_modify_qdisc+0xf48/0x2130 net/sched/sch_api.c:1813 rtnetlink_rcv_msg+0x3c9/0xe90 net/core/rtnetlink.c:6953 netlink_rcv_skb+0x155/0x420 net/netlink/af_netlink.c:2534 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline] netlink_unicast+0x53a/0x7f0 net/netlink/af_netlink.c:1339 netlink_sendmsg+0x8d1/0xdd0 net/netlink/af_netlink.c:1883 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg net/socket.c:727 [inline] ____sys_sendmsg+0xa95/0xc70 net/socket.c:2566 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2620 __sys_sendmsg+0x16d/0x220 net/socket.c:2652 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd528a7cae9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd5297010c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007fd528b9bf80 RCX: 00007fd528a7cae9 RDX: 0000000000000000 RSI: 00000000200007c0 RDI: 0000000000000004 RBP: 00007fd528ac847a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007fd528b9bf80 R15: 00007ffce8e39a98 rcu: rcu_preempt kthread starved for 10505 jiffies! g10189 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:28664 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x116a/0x5de0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6878 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 3571 Comm: kworker/u8:9 Not tainted 6.16.0-rc4-syzkaller-g1f988d0788f5 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:write_comp_data+0x0/0x90 kernel/kcov.c:240 Code: 48 8b 05 3b 96 14 12 48 8b 80 30 16 00 00 c3 cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <49> 89 d2 49 89 f8 49 89 f1 65 48 8b 15 07 96 14 12 65 8b 05 18 96 RSP: 0018:ffffc9000d037898 EFLAGS: 00000202 RAX: 0000000000000001 RBX: ffff8880b84421e0 RCX: ffffffff81b001dd RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: dffffc0000000000 R13: 0000000000000003 R14: ffffed101708843d R15: ffff8880b853b580 FS: 0000000000000000(0000) GS:ffff888124815000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055fb71610da8 CR3: 000000000e382000 CR4: 00000000003526f0 Call Trace: csd_lock_wait kernel/smp.c:340 [inline] smp_call_function_many_cond+0xd9d/0x1510 kernel/smp.c:885 on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1052 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2691 [inline] smp_text_poke_batch_finish+0x27b/0xdb0 arch/x86/kernel/alternative.c:2901 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x376/0x550 kernel/jump_label.c:919 static_key_enable_cpuslocked+0x1b7/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:850 [inline] toggle_allocation_gate+0xfa/0x280 mm/kfence/core.c:842 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245