rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=2be/1/0x4000000000000002 softirq=10754/10754 fqs=0 (t=10501 jiffies g=6509 q=44) rcu: rcu_preempt kthread starved for 10502 jiffies! g6509 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 28536 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: 8242 Comm: syz-executor.0 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:__memcg_kmem_uncharge+0x8/0x2e0 mm/memcontrol.c:2909 Code: 07 00 74 12 48 81 c3 08 02 00 00 48 89 df 4c 89 f6 e8 dc 7d ff ff 5b 41 5e 5d c3 0f 1f 80 00 00 00 00 55 48 89 e5 41 57 41 56 <41> 55 41 54 53 50 89 f3 49 89 fc 48 b8 00 00 00 00 00 fc ff df 4c RSP: 0018:ffffc90002097748 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81486ea4 RBX: ffffea0002316e40 RCX: ffff88807f41e000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea0002316e40 RBP: ffffc90002097758 R08: 000000000003a768 R09: fffffbfff120248a R10: fffffbfff120248a R11: 0000000000000000 R12: ffff88808ba19520 R13: dffffc0000000000 R14: 1ffff110117432a4 R15: ffff8880a77f19e8 memcg_kmem_uncharge include/linux/memcontrol.h:1402 [inline] free_thread_stack+0x12e/0x590 kernel/fork.c:284 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_common kernel/sched/core.c:4236 [inline] preempt_schedule+0xdb/0x120 kernel/sched/core.c:4261 ___preempt_schedule+0x16/0x18 arch/x86/entry/thunk_64.S:50 __kunmap_atomic include/linux/highmem.h:102 [inline] clear_highpage include/linux/highmem.h:215 [inline] kernel_init_free_pages mm/page_alloc.c:1125 [inline] prep_new_page+0x161/0x2e0 mm/page_alloc.c:2171 get_page_from_freelist+0x850/0xaa0 mm/page_alloc.c:3695 __alloc_pages_nodemask+0x264/0x5d0 mm/page_alloc.c:4756 alloc_pages_vma+0x4f7/0xd50 mm/mempolicy.c:2170 wp_page_copy+0x20b/0x1ca0 mm/memory.c:2409 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: 0033:0x40e271 Code: 3d 23 9e 34 00 00 0f 85 d8 08 00 00 e8 18 a9 04 00 85 c0 89 c5 0f 88 39 06 00 00 0f 84 ba 05 00 00 89 c6 bf 14 01 4c 00 31 c0 5a 3b ff ff c7 44 24 30 00 00 00 00 e8 2d 43 ff ff 49 89 c6 48 RSP: 002b:00007ffc19294770 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000458c4a RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00000000004c0114 RBP: 0000000000000002 R08: 0000000000000001 R09: 0000000001c08940 R10: 0000000001c08c10 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffc192947a0 R14: 0000000000000000 R15: 00007ffc192947b0