rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=0af/1/0x4000000000000000 softirq=6625/6626 fqs=2 (detected by 1, t=10502 jiffies, g=7205, q=201) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4189 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:match_held_lock+0x0/0xb0 kernel/locking/lockdep.c:5070 Code: db 85 c0 74 d8 83 3d 46 d2 c0 03 00 75 cf 48 c7 c7 c0 16 0b 8a 48 c7 c6 00 17 0b 8a e8 99 34 f5 ff 0f 0b eb b6 e8 f0 fa ff ff 01 00 00 00 48 39 77 10 74 6c 53 81 7f 20 00 00 10 00 72 5f 48 RSP: 0018:ffffc90000007c30 EFLAGS: 00000083 RAX: 0000000000000002 RBX: ffff88807cd01dc0 RCX: 0000000000000000 RDX: 0000000000010000 RSI: ffff88807ae4b300 RDI: ffff88807cd028d8 RBP: 00000000ffffffff R08: 0000000000000004 R09: 0000000000000003 R10: fffff52000000f80 R11: 1ffff92000000f80 R12: 0000000000000001 R13: 0000000000000046 R14: ffff88807ae4b300 R15: ffff88807cd028d8 FS: 0000555574f47500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c33224b CR3: 00000000619e2000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_is_held kernel/locking/lockdep.c:5366 [inline] lock_is_held_type+0xa6/0x190 kernel/locking/lockdep.c:5666 lock_is_held include/linux/lockdep.h:287 [inline] advance_sched+0x69/0x940 net/sched/sch_taprio.c:717 __run_hrtimer kernel/time/hrtimer.c:1690 [inline] __hrtimer_run_queues+0x53d/0xc40 kernel/time/hrtimer.c:1754 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:tomoyo_check_path_acl+0x2f/0x1c0 security/tomoyo/file.c:258 Code: 41 55 41 54 53 49 89 f6 48 89 fb 49 bd 00 00 00 00 00 fc ff df e8 f1 0c dc fd 4d 8d 7e 1a 4c 89 f8 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 2d 01 00 00 45 0f b7 27 4c 8d 7b 28 4c 89 f8 48 c1 e8 RSP: 0018:ffffc90002f4f8f8 EFLAGS: 00000a06 RAX: 0000000000000000 RBX: ffffc90002f4fa20 RCX: ffff88807cd01dc0 RDX: 0000000000000000 RSI: ffff88807d3f2800 RDI: ffffc90002f4fa20 RBP: ffff88807d3f2800 R08: ffff88807cd01dc0 R09: 0000000000000003 R10: 0000000000000009 R11: 0000000000000000 R12: 0000000000000000 R13: dffffc0000000000 R14: ffff88807d3f2800 R15: ffff88807d3f281a tomoyo_check_acl+0x132/0x3f0 security/tomoyo/domain.c:175 tomoyo_path_permission+0x1b4/0x380 security/tomoyo/file.c:586 tomoyo_path_perm+0x3d9/0x510 security/tomoyo/file.c:838 security_inode_getattr+0xcf/0x120 security/security.c:1348 vfs_getattr+0x26/0x3a0 fs/stat.c:157 vfs_statx+0x149/0x4d0 fs/stat.c:225 vfs_fstatat fs/stat.c:243 [inline] __do_sys_newfstatat fs/stat.c:411 [inline] __se_sys_newfstatat fs/stat.c:405 [inline] __x64_sys_newfstatat+0x12c/0x1b0 fs/stat.c:405 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f577d3f95ba Code: 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 0b 00 00 00 66 2e 0f 1f 84 00 00 00 00 00 90 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 c7 c2 a8 ff ff ff f7 RSP: 002b:00007ffe26e18358 EFLAGS: 00000286 ORIG_RAX: 0000000000000106 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f577d3f95ba RDX: 00007ffe26e18380 RSI: 00007ffe26e18410 RDI: 00000000ffffff9c RBP: 00007ffe26e18410 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000286 R12: 00007ffe26e194a0 R13: 00007f577d47dd7d R14: 0000000000011fbb R15: 00007ffe26e194e0 rcu: rcu_preempt kthread starved for 10498 jiffies! g7205 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:27200 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 4414 Comm: syz.1.31 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 Call Trace: dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106 nmi_cpu_backtrace+0x397/0x3d0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline] rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487 print_other_cpu_stall+0x10c8/0x1220 kernel/rcu/tree_stall.h:592 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline] rcu_pending kernel/rcu/tree.c:3936 [inline] rcu_sched_clock_irq+0x831/0x1110 kernel/rcu/tree.c:2619 update_process_times+0x193/0x200 kernel/time/timer.c:1818 tick_sched_handle kernel/time/tick-sched.c:254 [inline] tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1690 [inline] __hrtimer_run_queues+0x4fe/0xc40 kernel/time/hrtimer.c:1754 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1816 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline] __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline] sysvec_apic_timer_interrupt+0x9b/0xc0 arch/x86/kernel/apic/apic.c:1108 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:csd_lock_wait kernel/smp.c:440 [inline] RIP: 0010:smp_call_function_many_cond+0xb88/0xd70 kernel/smp.c:969 Code: b6 44 05 00 84 c0 0f 85 9d 00 00 00 41 8b 1c 24 89 de 83 e6 01 31 ff e8 66 49 0b 00 83 e3 01 75 07 e8 fc 45 0b 00 eb 43 f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 44 05 00 84 c0 75 11 41 f7 RSP: 0018:ffffc9000347fbe0 EFLAGS: 00000246 RAX: ffffffff816c854b RBX: 0000000000000001 RCX: 0000000000080000 RDX: ffffc90005b99000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc9000347fd20 R08: dffffc0000000000 R09: fffffbfff1ff783c R10: fffffbfff1ff783c R11: 1ffffffff1ff783b R12: ffff8880b9042848 R13: 1ffff11017208509 R14: ffff8880b913b3c0 R15: 0000000000000000 on_each_cpu_cond_mask+0x3b/0x80 kernel/smp.c:1135 on_each_cpu include/linux/smp.h:71 [inline] hardware_enable_all+0x7a/0x120 virt/kvm/kvm_main.c:4921 kvm_create_vm virt/kvm/kvm_main.c:1148 [inline] kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:4754 [inline] kvm_dev_ioctl+0x1239/0x2040 virt/kvm/kvm_main.c:4809 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f1fd60f8ec9 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:00007f1fd4360038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f1fd634ffa0 RCX: 00007f1fd60f8ec9 RDX: 0000000000000000 RSI: 000000000000ae01 RDI: 0000000000000003 RBP: 00007f1fd617bf91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1fd6350038 R14: 00007f1fd634ffa0 R15: 00007ffe2a0ce958