rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (0 ticks this GP) idle=7954/1/0x4000000000000000 softirq=45860/45861 fqs=5 rcu: (detected by 1, t=10502 jiffies, g=43689, q=119 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 10817 Comm: syz.3.1730 Not tainted 6.16.0-rc2-syzkaller-00087-g24770983ccfe #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] RIP: 0010:cpumask_test_cpu include/linux/cpumask.h:638 [inline] RIP: 0010:cpu_online include/linux/cpumask.h:1197 [inline] RIP: 0010:trace_hrtimer_expire_entry include/trace/events/timer.h:259 [inline] RIP: 0010:__run_hrtimer kernel/time/hrtimer.c:1758 [inline] RIP: 0010:__hrtimer_run_queues+0x439/0xc60 kernel/time/hrtimer.c:1825 Code: ec 11 00 65 44 8b 2d 6a 80 ee 10 bf 07 00 00 00 44 89 ee e8 b9 f0 11 00 41 83 fd 07 0f 87 cb 02 00 00 e8 6a ec 11 00 45 89 ef <41> c1 ed 06 4a 8d 3c ed f0 0d a1 8f be 08 00 00 00 e8 e1 6c 75 00 RSP: 0018:ffffc90000007d40 EFLAGS: 00000006 RAX: ffffffff81ae6fe6 RBX: ffff8880b8627c08 RCX: ffff88805a351e00 RDX: 0000000000010000 RSI: 0000000000000000 RDI: 0000000000000007 RBP: ffffc90000007e90 R08: ffff8880b8627ac3 R09: 1ffff110170c4f58 R10: dffffc0000000000 R11: ffffed10170c4f59 R12: ffff88807e8dd340 R13: 0000000000000000 R14: ffffffff8985f900 R15: 0000000000000000 FS: 00007fc6f3ca86c0(0000) GS:ffff888125c51000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30819ff8 CR3: 00000000683d5000 CR4: 0000000000350ef0 Call Trace: 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:__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 ab 0c 5f 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 f8 27 f6 65 8b 05 3c 14 34 07 85 c0 74 40 48 c7 04 24 0e 36 RSP: 0018:ffffc9000431fb60 EFLAGS: 00000206 RAX: 4319eb8ffe8f7600 RBX: 0000000000000216 RCX: 4319eb8ffe8f7600 RDX: 0000000000000007 RSI: ffffffff8d9823c9 RDI: 0000000000000001 RBP: ffffc9000431fbf0 R08: ffffffff8fa10df7 R09: 1ffffffff1f421be R10: dffffc0000000000 R11: fffffbfff1f421bf R12: dffffc0000000000 R13: ffff8880b8627ac0 R14: ffff8880b8627ac0 R15: 1ffff92000863f6c clock_was_set+0x63b/0x7c0 kernel/time/hrtimer.c:972 do_settimeofday64+0x2ec/0x5e0 kernel/time/timekeeping.c:1407 __do_sys_clock_settime kernel/time/posix-timers.c:1132 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1116 [inline] __x64_sys_clock_settime+0x22c/0x280 kernel/time/posix-timers.c:1116 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: 0033:0x7fc6f2d8e929 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:00007fc6f3ca8038 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007fc6f2fb5fa0 RCX: 00007fc6f2d8e929 RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000 RBP: 00007fc6f2e10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fc6f2fb5fa0 R15: 00007ffed4e5a308 rcu: rcu_preempt kthread starved for 10492 jiffies! g43689 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:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 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: 59 Comm: kworker/u8:4 Not tainted 6.16.0-rc2-syzkaller-00087-g24770983ccfe #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:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xf6e/0x12d0 kernel/smp.c:885 Code: 89 ee 83 e6 01 31 ff e8 70 78 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 1b 74 0b 00 eb 37 f3 90 43 0f b6 04 2c <84> c0 75 10 41 f7 07 01 00 00 00 74 1e e8 00 74 0b 00 eb e5 44 89 RSP: 0018:ffffc9000210f6a0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b873cb40 RCX: ffff88801c333c00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000210f800 R08: ffffffff8fa10df7 R09: 1ffffffff1f421be R10: dffffc0000000000 R11: fffffbfff1f421bf R12: 1ffff110170c86b5 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b86435a8 FS: 0000000000000000(0000) GS:ffff888125d51000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b3201cff8 CR3: 000000000df38000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 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+0x5e0/0x1100 arch/x86/kernel/alternative.c:2901 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3321 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402 kthread+0x711/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 vkms_vblank_simulate: vblank timer overrun