rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=a934/1/0x4000000000000000 softirq=114947/114948 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P21639 rcu: (detected by 1, t=10502 jiffies, g=93741, q=314 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 21639 Comm: syz.1.4116 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:869 [inline] RIP: 0010:advance_sched+0xabc/0xc90 net/sched/sch_taprio.c:992 Code: 4c 89 ef e8 d6 07 c7 ff e8 31 a7 e1 01 89 c5 31 ff 89 c6 e8 b6 9b 1c f8 85 ed 74 10 e8 5d 31 03 f8 84 c0 74 0e e8 64 97 1c f8 56 e8 5d 97 1c f8 eb 4f e8 06 a7 e1 01 89 c5 31 ff 89 c6 e8 8b RSP: 0018:ffffc90000007c70 EFLAGS: 00000006 RAX: ffffffff89a341bc RBX: ffffffff89a340f8 RCX: ffff888027fd8000 RDX: 0000000000010000 RSI: ffffffff8c03aa40 RDI: ffffffff8c03aa00 RBP: 0000000000000001 R08: ffff88807c51415f R09: 1ffff1100f8a282b R10: dffffc0000000000 R11: ffffed100f8a282c R12: ffff88807c514360 R13: ffff88807c514000 R14: 18727ff62c9ffc04 R15: ffff8880285de800 FS: 00007f80f69a96c0(0000) GS:ffff8881259e7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3a2100af98 CR3: 0000000030eca000 CR4: 00000000003526f0 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1777 [inline] __hrtimer_run_queues+0x52c/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:finish_task_switch+0x26b/0x950 kernel/sched/core.c:5228 Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 e9 27 05 00 00 4c 8b 75 d0 4c 89 e7 e8 7f 45 f6 09 e8 4a 52 36 00 fb 4c 8b 65 c0 <49> 8d bc 24 58 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0 RSP: 0018:ffffc90002eb6ff8 EFLAGS: 00000282 RAX: fb4250fe8ef2b000 RBX: 0000000000000000 RCX: fb4250fe8ef2b000 RDX: 0000000000000006 RSI: ffffffff8dba2d53 RDI: ffffffff8c03aa60 RBP: ffffc90002eb7050 R08: ffffffff8fc39677 R09: 1ffffffff1f872ce R10: dffffc0000000000 R11: fffffbfff1f872cf R12: ffff888027fd8000 R13: dffffc0000000000 R14: ffff88802d81bc80 R15: ffff8880b863ab98 context_switch kernel/sched/core.c:5363 [inline] __schedule+0x17a0/0x4cc0 kernel/sched/core.c:6964 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7291 irqentry_exit+0x6f/0x90 kernel/entry/common.c:211 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x15/0x360 kernel/locking/lockdep.c:5828 Code: 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 57 41 56 41 55 41 54 53 48 83 ec 60 4d 89 ce <45> 89 c7 41 89 cc 89 54 24 04 89 f3 49 89 fd 48 8b ac 24 98 00 00 RSP: 0018:ffffc90002eb73f8 EFLAGS: 00000282 RAX: 0000000000000001 RBX: ffffffff84c0c5e9 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e33d260 RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffc90002eb75b8 R11: ffffffff81ac5170 R12: 1ffff920005d6ead R13: ffffc90002eb75a0 R14: 0000000000000000 R15: ffffffff8173bd25 rcu_lock_acquire include/linux/rcupdate.h:331 [inline] rcu_read_lock include/linux/rcupdate.h:841 [inline] class_rcu_constructor include/linux/rcupdate.h:1169 [inline] unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:56 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:77 unpoison_slab_object mm/kasan/common.c:342 [inline] __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:368 kasan_slab_alloc include/linux/kasan.h:252 [inline] slab_post_alloc_hook mm/slub.c:4945 [inline] kmem_cache_alloc_bulk_noprof+0x44e/0x5d0 mm/slub.c:7413 __io_alloc_req_refill+0x9d/0x340 io_uring/io_uring.c:1056 io_alloc_req io_uring/io_uring.h:543 [inline] io_submit_sqes+0xc29/0x1e60 io_uring/io_uring.c:2436 __do_sys_io_uring_enter io_uring/io_uring.c:3514 [inline] __se_sys_io_uring_enter+0x2df/0x2b20 io_uring/io_uring.c:3453 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: 0033:0x7f80f5b8eec9 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:00007f80f69a9038 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 00007f80f5de6090 RCX: 00007f80f5b8eec9 RDX: 000000000000ff98 RSI: 00000000000015f1 RDI: 0000000000000008 RBP: 00007f80f5c11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f80f5de6128 R14: 00007f80f5de6090 R15: 00007ffe21e97178 task:syz.1.4116 state:R running task stack:26536 pid:21639 tgid:21602 ppid:16758 task_flags:0x400140 flags:0x00080010 Call Trace: rcu: rcu_preempt kthread starved for 10502 jiffies! g93741 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:27288 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5360 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7046 [inline] schedule+0x165/0x360 kernel/sched/core.c:7061 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 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 21642 Comm: syz.3.4127 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd33/0x12d0 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 36 79 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 e1 74 0b 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 c5 74 RSP: 0018:ffffc900037bf5a0 EFLAGS: 00000246 RAX: ffffffff81b4645b RBX: 1ffff110170c8441 RCX: 0000000000080000 RDX: ffffc9001e369000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc900037bf720 R08: ffffffff8fc39677 R09: 1ffffffff1f872ce R10: dffffc0000000000 R11: fffffbfff1f872cf R12: ffff8880b8642208 R13: dffffc0000000000 R14: ffff8880b873b200 R15: 0000000000000000 FS: 00007f1abbe956c0(0000) GS:ffff888125ae7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c39c21b CR3: 0000000062088000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 on_each_cpu include/linux/smp.h:71 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2713 [inline] smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2923 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 static_key_slow_inc_cpuslocked+0x86/0x120 kernel/jump_label.c:168 static_key_slow_inc+0x1a/0x30 kernel/jump_label.c:191 kvm_create_lapic+0x110/0x400 arch/x86/kvm/lapic.c:2959 kvm_arch_vcpu_create+0x1ec/0x920 arch/x86/kvm/x86.c:12289 kvm_vm_ioctl_create_vcpu+0x429/0x930 virt/kvm/kvm_main.c:4207 kvm_vm_ioctl+0x7f7/0xc60 virt/kvm/kvm_main.c:5158 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583 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: 0033:0x7f1abaf8eec9 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:00007f1abbe95038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1abb1e5fa0 RCX: 00007f1abaf8eec9 RDX: 0000000000000000 RSI: 000000000000ae41 RDI: 0000000000000006 RBP: 00007f1abb011f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1abb1e6038 R14: 00007f1abb1e5fa0 R15: 00007ffcb56ff058