rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=852/1/0x4000000000000002 softirq=11200/11201 fqs=6 (t=10501 jiffies g=6601 q=369) rcu: rcu_preempt kthread starved for 10489 jiffies! g6601 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29032 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 NMI backtrace for cpu 1 CPU: 1 PID: 8203 Comm: syz-executor.1 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaf/0x1a0 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x174/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x15a/0x220 kernel/rcu/tree_stall.h:254 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline] check_cpu_stall kernel/rcu/tree_stall.h:529 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq+0xe25/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:free_thread_stack+0x151/0x590 kernel/fork.c:280 Code: 31 f6 e8 42 af 6e 00 43 80 3c 2e 00 74 08 4c 89 e7 e8 43 a4 69 00 49 8b 1c 24 48 83 c3 08 48 89 d8 48 c1 e8 03 42 80 3c 28 00 <74> 08 48 89 df e8 25 a4 69 00 48 8b 3b be fc ff ff ff e8 28 04 00 RSP: 0018:ffffc90002387708 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff110150799e1 RBX: ffff8880a83ccf08 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea00024d9a80 RBP: ffffc90002387740 R08: 000000000003a768 R09: ffffed101523373f R10: ffffed101523373f R11: 0000000000000000 R12: ffff8880a83ccfa0 R13: dffffc0000000000 R14: 1ffff110150799f4 R15: ffff8880a919b9e8 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 preempt_schedule_irq+0xc1/0x140 kernel/sched/core.c:4338 retint_kernel+0x1b/0x2b RIP: 0010:debug_lockdep_rcu_enabled+0x68/0xe0 kernel/rcu/update.c:252 Code: 04 38 84 c0 75 59 83 3d 65 cd e0 07 00 74 28 65 4c 8b 34 25 c0 1d 02 00 49 81 c6 94 08 00 00 4c 89 f0 48 c1 e8 03 42 8a 04 38 <84> c0 75 59 31 db 41 83 3e 00 0f 94 c3 89 d8 5b 41 5e 41 5f 5d c3 RSP: 0000:ffffc90002387950 EFLAGS: 00000a03 ORIG_RAX: ffffffffffffff13 RAX: 1ffff110131f2900 RBX: 0000000000000000 RCX: ffffffff815bbb47 RDX: 0000000000000000 RSI: 0000000000001257 RDI: ffffffff88bf4160 RBP: ffffc90002387968 R08: dffffc0000000000 R09: fffffbfff12877ed R10: fffffbfff12877ed R11: 0000000000000000 R12: 0000000000000000 R13: 1ffff110131f2842 R14: ffff888098f94a94 R15: dffffc0000000000 ___might_sleep+0x20/0x5e0 kernel/sched/core.c:6765 __might_sleep+0x8f/0x100 kernel/sched/core.c:6753 prepare_alloc_pages+0x278/0x460 mm/page_alloc.c:4695 __alloc_pages_nodemask+0xb2/0x5d0 mm/page_alloc.c:4744 alloc_pages_vma+0x4f7/0xd50 mm/mempolicy.c:2170 alloc_zeroed_user_highpage_movable include/linux/highmem.h:208 [inline] wp_page_copy+0x1e2/0x1ca0 mm/memory.c:2404 do_wp_page+0x5e4/0x16d0 mm/memory.c:2662 handle_pte_fault mm/memory.c:3961 [inline] __handle_mm_fault mm/memory.c:4075 [inline] handle_mm_fault+0x23c5/0x2890 mm/memory.c:4112 do_user_addr_fault+0x589/0xaf0 arch/x86/mm/fault.c:1441 __do_page_fault+0xd3/0x1f0 arch/x86/mm/fault.c:1506 do_page_fault+0x99/0xb0 arch/x86/mm/fault.c:1530 page_fault+0x39/0x40 arch/x86/entry/entry_64.S:1203 RIP: 0033:0x40f6c8 Code: 8b 34 c6 4a 8d 04 2e 48 3d ff ff ff 7e 0f 86 77 ff ff ff bf 64 fe 4b 00 31 c0 e8 13 27 ff ff 31 ff e8 5c 23 ff ff 0f 1f 40 00 <89> 3c b5 00 00 73 00 eb b6 31 ed 0f 1f 44 00 00 80 3d 7e 2f 66 00 RSP: 002b:00007ffc986df620 EFLAGS: 00010246 RAX: 000000008e26ef3a RBX: 000000007e9131e4 RCX: 0000001b34420000 RDX: 0000000000000000 RSI: 0000000000000f3a RDI: ffffffff8e26ef3a RBP: 000000000000000d R08: 000000008e26ef3a R09: 000000008e26ef3e R10: 00007ffc986df7c0 R11: 0000000000000246 R12: 000000000075bfa8 R13: 0000000080000000 R14: 00007f7ca27c7008 R15: 000000000000000d