rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=9104/1/0x4000000000000000 softirq=164243/164243 fqs=11 rcu: (detected by 0, t=10502 jiffies, g=142765, q=2264 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 18452 Comm: syz.7.4203 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:num_possible_cpus include/linux/cpumask.h:1222 [inline] RIP: 0010:mm_get_cid kernel/sched/sched.h:3880 [inline] RIP: 0010:sched_mm_cid_fork+0x661/0x10e0 kernel/sched/core.c:10954 Code: 00 49 c7 c4 b8 2e 26 8e 49 c1 ec 03 41 bd 00 00 00 80 eb 0a 89 e8 f7 d8 0f 81 09 fe ff ff f3 90 48 b8 00 00 00 00 00 fc ff df <41> 0f b6 04 04 84 c0 75 40 44 8b 35 e7 6f 91 0c 48 89 df 4c 89 f6 RSP: 0018:ffffc900047efc48 EFLAGS: 00000887 RAX: dffffc0000000000 RBX: ffff8880312017d0 RCX: 0000000080000001 RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff8880312017d0 RBP: 0000000080000000 R08: 1ffff110062401a9 R09: 0000000000000000 R10: ffff888031200e8c R11: fffff520008fdf78 R12: 1ffffffff1c4c5d7 R13: 0000000080000000 R14: 0000000000000002 R15: ffff888031200c40 FS: 00007fd7772f16c0(0000) GS:ffff8881253a0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffc748214d CR3: 0000000046858000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000009951 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: bprm_execve+0xdb7/0x1510 fs/exec.c:1771 do_execveat_common+0x50d/0x690 fs/exec.c:1846 __do_sys_execveat fs/exec.c:1941 [inline] __se_sys_execveat fs/exec.c:1934 [inline] __x64_sys_execveat+0xc7/0xf0 fs/exec.c:1934 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd77639ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd7772f1028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142 RAX: ffffffffffffffda RBX: 00007fd776615fa0 RCX: 00007fd77639ce59 RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000004 RBP: 00007fd776432d6f R08: 0000000000001000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd776616038 R14: 00007fd776615fa0 R15: 00007fd77673fa48 rcu: rcu_preempt kthread starved for 10480 jiffies! g142765 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:27544 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0x164/0x360 kernel/sched/core.c:7283 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x389/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 0 UID: 0 PID: 18450 Comm: syz.0.4202 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_single+0x39f/0x5b0 kernel/smp.c:702 Code: 27 44 89 e6 83 e6 01 31 ff e8 6d 20 0c 00 41 83 e4 01 75 11 e8 22 1c 0c 00 4d 89 ec eb 41 e8 18 1c 0c 00 eb 3a 4d 89 ec f3 90 <42> 0f b6 04 33 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 fa 1b 0c RSP: 0018:ffffc90004b1ea80 EFLAGS: 00000246 RAX: ffffffff81b99be6 RBX: 1ffff92000963d5d RCX: 0000000000080000 RDX: ffffc90015451000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc90004b1eb78 R08: ffffc90004b1e9c7 R09: 1ffff92000963d38 R10: dffffc0000000000 R11: fffff52000963d39 R12: 1ffff92000963d58 R13: 1ffff92000963d58 R14: dffffc0000000000 R15: ffffc90004b1eae8 FS: 00007f2d90ffa6c0(0000) GS:ffff8881252a0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b30312ff8 CR3: 0000000087db0000 CR4: 00000000003526f0 Call Trace: loaded_vmcs_clear arch/x86/kvm/vmx/vmx.c:839 [inline] vmx_vcpu_load_vmcs+0xcd/0x5d0 arch/x86/kvm/vmx/vmx.c:1500 vmx_vcpu_load+0x1b0/0x260 arch/x86/kvm/vmx/vmx.c:1558 kvm_arch_vcpu_load+0x25d/0xab0 arch/x86/kvm/x86.c:5184 kvm_sched_in+0x7c/0xe0 virt/kvm/kvm_main.c:6390 __fire_sched_in_preempt_notifiers kernel/sched/core.c:4908 [inline] fire_sched_in_preempt_notifiers kernel/sched/core.c:4914 [inline] finish_task_switch+0xb14/0xbe0 kernel/sched/core.c:5255 context_switch kernel/sched/core.c:5391 [inline] __schedule+0x1829/0x5740 kernel/sched/core.c:7189 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x8b0 kernel/entry/common.c:164 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__vmcs_readl arch/x86/kvm/vmx/vmx_ops.h:97 [inline] RIP: 0010:vmcs_read32 arch/x86/kvm/vmx/vmx_ops.h:167 [inline] RIP: 0010:vmx_read_guest_seg_limit arch/x86/kvm/vmx/vmx.c:881 [inline] RIP: 0010:vmx_get_segment+0x553/0xaf0 arch/x86/kvm/vmx/vmx.c:3616 Code: 44 24 08 48 c1 e0 04 4c 8d a0 48 b1 c4 8b 4c 89 e0 48 c1 e8 03 42 0f b6 04 30 84 c0 0f 85 dc 04 00 00 45 8b 24 24 44 0f 78 e5 <0f> 86 6c 05 00 00 e8 f2 ff 69 00 4c 89 e8 48 c1 e8 03 42 0f b6 04 RSP: 0018:ffffc90004b1f100 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 000000000000000c RCX: 0000000000080000 RDX: ffffc90015451000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: 00000000000fffff R08: ffff88807d5bd617 R09: 1ffff1100fab7ac2 R10: dffffc0000000000 R11: ffffed100fab7ac3 R12: 0000000000004808 R13: ffff88807d5bf738 R14: dffffc0000000000 R15: ffffc90004b1f168 data_segment_valid+0x3d/0x100 arch/x86/kvm/vmx/vmx.c:3842 __vmx_guest_state_valid+0x965/0xb50 arch/x86/kvm/vmx/vmx.c:3942 vmx_guest_state_valid arch/x86/kvm/vmx/vmx.h:702 [inline] vmx_emulation_required arch/x86/kvm/vmx/vmx.c:1607 [inline] vmx_set_cr0+0x1490/0x1e30 arch/x86/kvm/vmx/vmx.c:3482 prepare_vmcs02 arch/x86/kvm/vmx/nested.c:2781 [inline] nested_vmx_enter_non_root_mode+0x4272/0x9c60 arch/x86/kvm/vmx/nested.c:3684 nested_vmx_run+0x5fb/0xc30 arch/x86/kvm/vmx/nested.c:3849 __vmx_handle_exit arch/x86/kvm/vmx/vmx.c:6830 [inline] vmx_handle_exit+0xff8/0x16f0 arch/x86/kvm/vmx/vmx.c:6840 vcpu_enter_guest arch/x86/kvm/x86.c:11613 [inline] vcpu_run+0x5c77/0x7860 arch/x86/kvm/x86.c:11770 kvm_arch_vcpu_ioctl_run+0x11e6/0x20d0 arch/x86/kvm/x86.c:12125 kvm_vcpu_ioctl+0xa62/0xfd0 virt/kvm/kvm_main.c:4470 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+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2d9019ce59 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f2d90ffa028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f2d90415fa0 RCX: 00007f2d9019ce59 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 RBP: 00007f2d90232d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f2d90416038 R14: 00007f2d90415fa0 R15: 00007f2d9053fa48