rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11745/1:b..l (detected by 1, t=10502 jiffies, g=24537, q=107) task:systemd-udevd state:R running task stack:25664 pid:11745 ppid: 2945 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb72/0x1460 kernel/sched/core.c:6287 preempt_schedule_irq+0xf7/0x1c0 kernel/sched/core.c:6687 irqentry_exit+0x56/0x90 kernel/entry/common.c:425 asm_sysvec_reschedule_ipi+0x12/0x20 RIP: 0010:seqcount_lockdep_reader_access+0x1de/0x230 include/linux/seqlock.h:106 Code: 5e e8 f6 6a a5 ff 4d 85 f6 48 bb 00 00 00 00 00 fc ff df 75 07 e8 e2 6a a5 ff eb 06 e8 db 6a a5 ff fb 48 c7 04 24 0e 36 e0 45 <4a> c7 04 23 00 00 00 00 66 42 c7 44 23 09 00 00 42 c6 44 23 0b 00 RSP: 0018:ffffc9000458f9a0 EFLAGS: 00000293 RAX: ffffffff81de4af5 RBX: dffffc0000000000 RCX: ffff888079bed580 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000458fa58 R08: ffffffff81de4ad0 R09: ffffed10173864a2 R10: ffffed10173864a2 R11: 0000000000000000 R12: 1ffff920008b1f34 R13: ffffc9000458f9c0 R14: 0000000000000200 R15: 0000000000000046 set_root+0x178/0x3e0 fs/namei.c:940 nd_jump_root+0x2a0/0x410 fs/namei.c:961 path_init+0x354/0x11f0 fs/namei.c:2359 path_parentat fs/namei.c:2495 [inline] filename_parentat+0x271/0x7b0 fs/namei.c:2519 do_unlinkat+0x13c/0xa10 fs/namei.c:4140 __do_sys_unlink fs/namei.c:4217 [inline] __se_sys_unlink fs/namei.c:4215 [inline] __x64_sys_unlink+0x45/0x50 fs/namei.c:4215 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7efea6faa0e7 RSP: 002b:00007ffe50f626d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000558ff3dc0e80 RCX: 00007efea6faa0e7 RDX: 00007ffe50f625b0 RSI: 00007ffe50f625b0 RDI: 00007ffe50f626e0 RBP: 000000000000029f R08: 00000000000001c0 R09: 0000000000000013 R10: 00007ffe50f626c0 R11: 0000000000000246 R12: 00007ffe50f626e0 R13: 0000558ff3dc0e80 R14: 0000000000000003 R15: 000000000000000e rcu: rcu_preempt kthread starved for 10496 jiffies! g24537 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:26544 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0xb72/0x1460 kernel/sched/core.c:6287 schedule+0x14b/0x210 kernel/sched/core.c:6366 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x1fd/0x770 kernel/rcu/tree.c:1957 rcu_gp_kthread+0xa5/0x350 kernel/rcu/tree.c:2130 kthread+0x453/0x480 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 12134 Comm: syz-executor.3 Not tainted 5.15.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1dc/0x2d8 lib/dump_stack.c:106 nmi_cpu_backtrace+0x45f/0x490 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation+0x1ff/0x270 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3880 [inline] rcu_sched_clock_irq+0x23d5/0x2bc0 kernel/rcu/tree.c:2599 update_process_times+0x197/0x200 kernel/time/timer.c:1785 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:lock_is_held_type+0x141/0x190 Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 d8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc900065766b8 EFLAGS: 00000206 RAX: 5ba3c5387ff0c200 RBX: 0000000000000000 RCX: 0000000000040000 RDX: ffffc9000f875000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000004 R08: ffffffff81bd2843 R09: ffffed10173a64a2 R10: ffffed10173a64a2 R11: 0000000000000000 R12: 0000000000000246 R13: ffff888072e5b900 R14: 00000000ffffffff R15: ffffffff8c942468 lock_is_held include/linux/lockdep.h:283 [inline] task_css include/linux/cgroup.h:494 [inline] mem_cgroup_from_task+0x4c/0x100 mm/memcontrol.c:870 count_memcg_event_mm+0x13d/0x390 include/linux/memcontrol.h:1061 handle_mm_fault+0x136/0x2560 mm/memory.c:4781 faultin_page mm/gup.c:937 [inline] __get_user_pages+0x4da/0x11f0 mm/gup.c:1158 __get_user_pages_locked mm/gup.c:1343 [inline] get_user_pages_unlocked+0x224/0x8f0 mm/gup.c:2067 hva_to_pfn_slow+0x128/0x510 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2269 hva_to_pfn+0x233/0xbe0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2401 kvm_faultin_pfn+0x44c/0x900 arch/x86/kvm/mmu/mmu.c:3957 direct_page_fault+0x11f0/0x2b00 arch/x86/kvm/mmu/mmu.c:3992 kvm_mmu_do_page_fault arch/x86/kvm/mmu.h:127 [inline] kvm_mmu_page_fault+0x1a3/0x13d0 arch/x86/kvm/mmu/mmu.c:5287 vmx_handle_exit+0x26/0x160 arch/x86/kvm/vmx/vmx.c:6055 vcpu_enter_guest+0x6aa9/0x9650 arch/x86/kvm/x86.c:9760 vcpu_run+0x4d3/0xe50 arch/x86/kvm/x86.c:9827 kvm_arch_vcpu_ioctl_run+0x5c0/0xdb0 arch/x86/kvm/x86.c:10059 kvm_vcpu_ioctl+0x894/0xe20 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3779 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f044c64dae9 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 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0449bc3188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f044c760f60 RCX: 00007f044c64dae9 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 RBP: 00007f044c6a7f25 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fff83ec9cdf R14: 00007f0449bc3300 R15: 0000000000022000 sched: RT throttling activated ---------------- Code disassembly (best guess): 0: 5e pop %rsi 1: e8 f6 6a a5 ff callq 0xffa56afc 6: 4d 85 f6 test %r14,%r14 9: 48 bb 00 00 00 00 00 movabs $0xdffffc0000000000,%rbx 10: fc ff df 13: 75 07 jne 0x1c 15: e8 e2 6a a5 ff callq 0xffa56afc 1a: eb 06 jmp 0x22 1c: e8 db 6a a5 ff callq 0xffa56afc 21: fb sti 22: 48 c7 04 24 0e 36 e0 movq $0x45e0360e,(%rsp) 29: 45 * 2a: 4a c7 04 23 00 00 00 movq $0x0,(%rbx,%r12,1) <-- trapping instruction 31: 00 32: 66 42 c7 44 23 09 00 movw $0x0,0x9(%rbx,%r12,1) 39: 00 3a: 42 c6 44 23 0b 00 movb $0x0,0xb(%rbx,%r12,1)