rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=bd4c/1/0x4000000000000000 softirq=56260/56261 fqs=1 rcu: (detected by 0, t=10502 jiffies, g=64909, q=37 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 14443 Comm: syz.2.1793 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:get_current arch/x86/include/asm/current.h:41 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x60 kernel/kcov.c:215 Code: 00 00 f3 0f 1e fa 53 48 89 fb e8 13 00 00 00 48 8b 3d 0c fe c4 0c 48 89 de 5b e9 33 89 56 00 cc cc cc f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 20 28 7e 7e 65 8b 15 21 28 7e 7e 81 e2 00 01 ff 00 74 RSP: 0018:ffffc900001f0bf8 EFLAGS: 00000086 RAX: ffffffff889dab86 RBX: ffff88801a2ce2c0 RCX: dffffc0000000000 RDX: ffff88805d760c00 RSI: ffff88805d760400 RDI: ffff88801a2ce2c0 RBP: ffff88805d760d50 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff5200003e17c R12: ffff88801a2ce340 R13: dffffc0000000000 R14: ffff88805d760400 R15: ffff88805d760c00 FS: 0000555576aa1500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c32d958 CR3: 000000005b20a000 CR4: 00000000003506e0 Call Trace: taprio_set_budgets+0x26/0x390 net/sched/sch_taprio.c:675 advance_sched+0x964/0xc80 net/sched/sch_taprio.c:993 __run_hrtimer kernel/time/hrtimer.c:1750 [inline] __hrtimer_run_queues+0x51e/0xc40 kernel/time/hrtimer.c:1814 hrtimer_interrupt+0x3c9/0x9c0 kernel/time/hrtimer.c:1876 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1077 [inline] __sysvec_apic_timer_interrupt+0xfb/0x3b0 arch/x86/kernel/apic/apic.c:1094 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1088 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687 RIP: 0010:seqcount_lockdep_reader_access+0x17f/0x1c0 include/linux/seqlock.h:105 Code: 00 4d 85 e4 75 16 e8 d0 8f 0f 00 eb 15 e8 c9 8f 0f 00 e8 e4 cd f8 08 4d 85 e4 74 ea e8 ba 8f 0f 00 fb 48 c7 04 24 0e 36 e0 45 <4b> c7 04 3e 00 00 00 00 66 43 c7 44 3e 09 00 00 43 c6 44 3e 0b 00 RSP: 0018:ffffc9000e267d20 EFLAGS: 00000293 RAX: ffffffff8175ffd6 RBX: 0000000000000000 RCX: ffff888022bf8000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000e267dd0 R08: ffffffff8e4a8b6f R09: 1ffffffff1c9516d R10: dffffc0000000000 R11: fffffbfff1c9516e R12: 0000000000000200 R13: 0000000002faf080 R14: 1ffff92001c4cfa4 R15: dffffc0000000000 timekeeping_get_delta kernel/time/timekeeping.c:254 [inline] timekeeping_get_ns kernel/time/timekeeping.c:388 [inline] ktime_get+0x7f/0x280 kernel/time/timekeeping.c:848 futex_init_timeout kernel/futex/syscalls.c:158 [inline] __do_sys_futex kernel/futex/syscalls.c:177 [inline] __se_sys_futex+0x2b2/0x3f0 kernel/futex/syscalls.c:164 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f29c2b8efc9 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:00007ffeccfc5038 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00000000000f085c RCX: 00007f29c2b8efc9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f29c2de618c RBP: 0000000000000032 R08: 0000000000745d1e R09: 00000018ccfc532f R10: 00007ffeccfc5130 R11: 0000000000000246 R12: 00007f29c2de618c R13: 00007ffeccfc5130 R14: 00000000000f088e R15: 00007ffeccfc5150 rcu: rcu_preempt kthread starved for 10500 jiffies! g64909 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:27192 pid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5380 [inline] __schedule+0x14d2/0x44d0 kernel/sched/core.c:6699 schedule+0xbd/0x170 kernel/sched/core.c:6773 schedule_timeout+0x160/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x302/0x1560 kernel/rcu/tree.c:1667 rcu_gp_kthread+0x99/0x380 kernel/rcu/tree.c:1866 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 9542 Comm: kworker/u4:18 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:311 [inline] RIP: 0010:smp_call_function_many_cond+0xde4/0x1130 kernel/smp.c:855 Code: 89 ee 83 e6 01 31 ff e8 da d6 0a 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 15 d3 0a 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 f9 d2 0a 00 eb e4 44 RSP: 0018:ffffc900037e7780 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff110171e82ad RCX: ffff888076813c00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900037e7900 R08: ffffffff90da8507 R09: 1ffffffff21b50a0 R10: dffffc0000000000 R11: fffffbfff21b50a1 R12: ffff8880b8f41568 R13: dffffc0000000000 R14: ffff8880b8e3d348 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000000cb30000 CR4: 00000000003506f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1022 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2222 [inline] text_poke_bp_batch+0x318/0x930 arch/x86/kernel/alternative.c:2432 text_poke_flush arch/x86/kernel/alternative.c:2623 [inline] text_poke_finish+0x30/0x50 arch/x86/kernel/alternative.c:2630 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x123/0x240 kernel/jump_label.c:207 static_key_enable+0x1a/0x20 kernel/jump_label.c:220 toggle_allocation_gate+0xaa/0x250 mm/kfence/core.c:831 process_one_work kernel/workqueue.c:2634 [inline] process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711 worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792 kthread+0x2fa/0x390 kernel/kthread.c:388 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293