rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10499 ticks this GP) idle=93e/1/0x4000000000000002 softirq=10843/10844 fqs=149 (t=10501 jiffies g=6661 q=231) rcu: rcu_preempt kthread starved for 10203 jiffies! g6661 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 28984 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 0 CPU: 0 PID: 8468 Comm: syz-executor.0 Not tainted 5.5.0-rc5-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:1517 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1579 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1641 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+0x18b/0x590 kernel/fork.c:284 Code: ff ff e8 28 04 00 00 43 80 3c 2e 00 74 08 4c 89 e7 e8 39 94 6a 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 1b 94 6a 00 48 8b 1b e9 82 ff ff ff e8 be 2b 2e RSP: 0018:ffffc900020b76d8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff1100d380a71 RBX: ffff888069c05388 RCX: 0000000000040000 RDX: ffffc90002149000 RSI: 000000000003ffff RDI: 0000000000040000 RBP: ffffc900020b7710 R08: 000000000003a728 R09: ffffed1011dcf2a9 R10: ffffed1011dcf2a9 R11: 0000000000000000 R12: ffff888069c05420 R13: dffffc0000000000 R14: 1ffff1100d380a84 R15: ffff88808ee79538 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 include/linux/gfp.h:496 [inline] __alloc_pages_node include/linux/gfp.h:509 [inline] alloc_pages_vma+0x94a/0xd50 mm/mempolicy.c:2151 do_huge_pmd_anonymous_page+0x883/0xe50 mm/huge_memory.c:758 create_huge_pmd mm/memory.c:3888 [inline] __handle_mm_fault mm/memory.c:4098 [inline] handle_mm_fault+0x2017/0x2890 mm/memory.c:4164 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: 0010:copy_user_generic_unrolled+0x89/0xc0 arch/x86/lib/copy_user_64.S:91 Code: 38 4c 89 47 20 4c 89 4f 28 4c 89 57 30 4c 89 5f 38 48 8d 76 40 48 8d 7f 40 ff c9 75 b6 89 d1 83 e2 07 c1 e9 03 74 12 4c 8b 06 <4c> 89 07 48 8d 76 08 48 8d 7f 08 ff c9 75 ee 21 d2 74 10 89 d1 8a RSP: 0018:ffffc900020b7e50 EFLAGS: 00010202 RAX: ffffffff839b2501 RBX: 0000000020000008 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffc900020b7e98 RDI: 0000000020000000 RBP: ffffc900020b7e80 R08: 0000000400000003 R09: fffff52000416fd4 R10: fffff52000416fd4 R11: 0000000000000000 R12: 0000000000000008 R13: 00007ffffffff000 R14: ffffc900020b7e98 R15: 0000000020000000 copy_to_user include/linux/uaccess.h:152 [inline] do_pipe2+0x79/0x230 fs/pipe.c:972 __do_sys_pipe2 fs/pipe.c:988 [inline] __se_sys_pipe2 fs/pipe.c:986 [inline] __x64_sys_pipe2+0x5a/0x70 fs/pipe.c:986 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45af49 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f259c27dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000125 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 000000000045af49 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000000 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f259c27e6d4 R13: 00000000004c90bd R14: 00000000004e1938 R15: 00000000ffffffff