rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13484 P13174/1:b..l rcu: (detected by 1, t=10502 jiffies, g=140245, q=575 ncpus=2) task:udevd state:R running task stack:24208 pid:13174 tgid:13174 ppid:4674 flags:0x00000002 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x17ae/0x4a10 kernel/sched/core.c:6529 preempt_schedule_common+0x84/0xd0 kernel/sched/core.c:6708 preempt_schedule+0xe1/0xf0 kernel/sched/core.c:6732 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1688 [inline] zap_pmd_range mm/memory.c:1736 [inline] zap_pud_range mm/memory.c:1765 [inline] zap_p4d_range mm/memory.c:1786 [inline] unmap_page_range+0x3818/0x42c0 mm/memory.c:1807 unmap_vmas+0x3cc/0x5f0 mm/memory.c:1897 exit_mmap+0x264/0xc80 mm/mmap.c:3412 __mmput+0x115/0x380 kernel/fork.c:1345 exit_mm+0x220/0x310 kernel/exit.c:571 do_exit+0x9b2/0x27f0 kernel/exit.c:869 do_group_exit+0x207/0x2c0 kernel/exit.c:1031 __do_sys_exit_group kernel/exit.c:1042 [inline] __se_sys_exit_group kernel/exit.c:1040 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1040 x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe9ebafca90 RSP: 002b:00007ffcc776a0a8 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fe9ebafca90 RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000007 R09: 9fbda96063898afe R10: 00000000ffffffff R11: 0000000000000202 R12: 000055acb5409fe0 R13: 00007ffcc776a0e8 R14: 0000000000000001 R15: 000055acb53e2910 task:syz.3.1097 state:R running task stack:23800 pid:13484 tgid:13483 ppid:12931 flags:0x00004002 Call Trace: sched_show_task+0x506/0x6d0 kernel/sched/core.c:7432 rcu_print_detail_task_stall_rnp kernel/rcu/tree_stall.h:262 [inline] print_other_cpu_stall+0x11f9/0x15a0 kernel/rcu/tree_stall.h:639 check_cpu_stall kernel/rcu/tree_stall.h:799 [inline] rcu_pending kernel/rcu/tree.c:4343 [inline] rcu_sched_clock_irq+0xa2c/0x10d0 kernel/rcu/tree.c:2670 update_process_times+0x1ce/0x230 kernel/time/timer.c:2485 tick_sched_handle kernel/time/tick-sched.c:276 [inline] tick_nohz_handler+0x37c/0x500 kernel/time/tick-sched.c:297 __run_hrtimer kernel/time/hrtimer.c:1689 [inline] __hrtimer_run_queues+0x551/0xd50 kernel/time/hrtimer.c:1753 hrtimer_interrupt+0x396/0x990 kernel/time/hrtimer.c:1815 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1032 [inline] __sysvec_apic_timer_interrupt+0x110/0x3f0 arch/x86/kernel/apic/apic.c:1049 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:prandom_u32_state+0x1e/0x180 lib/random32.c:55 Code: 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 41 57 41 56 41 54 53 49 89 fc 49 bf 00 00 00 00 00 fc ff df e8 32 f9 ec fc <4c> 89 e0 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 d4 00 00 00 41 8b RSP: 0018:ffffc900041f7898 EFLAGS: 00000246 RAX: ffffffff84a6932e RBX: ffffffff8e08aa58 RCX: 0000000000040000 RDX: ffffc90004b91000 RSI: 000000000003ffff RDI: 0000000000040000 RBP: 0000000000000001 R08: ffffffff81a2c01a R09: 1ffff110069cfb40 R10: dffffc0000000000 R11: ffffffffa0001ad4 R12: ffff8880b8936448 R13: dffffc0000000000 R14: 0000000000000000 R15: dffffc0000000000 ____bpf_user_rnd_u32 kernel/bpf/core.c:2836 [inline] bpf_user_rnd_u32+0x6a/0xc0 kernel/bpf/core.c:2824 bpf_prog_d4a52e119b87a762+0x47/0x4b bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline] __bpf_prog_run include/linux/filter.h:682 [inline] bpf_prog_run include/linux/filter.h:698 [inline] bpf_test_run+0x7b8/0xa90 net/bpf/test_run.c:433 bpf_prog_test_run_skb+0xc97/0x1820 net/bpf/test_run.c:1094 bpf_prog_test_run+0x33a/0x3b0 kernel/bpf/syscall.c:4313 __sys_bpf+0x48d/0x810 kernel/bpf/syscall.c:5728 __do_sys_bpf kernel/bpf/syscall.c:5817 [inline] __se_sys_bpf kernel/bpf/syscall.c:5815 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5815 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f76c4b7def9 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:00007f76c58a2038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141 RAX: ffffffffffffffda RBX: 00007f76c4d35f80 RCX: 00007f76c4b7def9 RDX: 0000000000000050 RSI: 0000000020000d80 RDI: 000000000000000a RBP: 00007f76c4bf09f6 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f76c4d35f80 R15: 00007ffdc9186e38 rcu: rcu_preempt kthread starved for 10469 jiffies! g140245 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:26048 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x17ae/0x4a10 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2034 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2236 kthread+0x2f0/0x390 kernel/kthread.c:389 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111