rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-....: (10499 ticks this GP) idle=482/1/0x4000000000000002 softirq=11102/11102 fqs=2739 (t=10501 jiffies g=6537 q=840) rcu: rcu_preempt kthread starved for 5023 jiffies! g6537 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: 8428 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:ffffc90001da7668 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff11014d9bd81 RBX: ffff8880a6cdec08 RCX: ffff88809f206280 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea0002999c00 RBP: ffffc90001da76a0 R08: dffffc0000000000 R09: fffffbfff124248a R10: fffffbfff124248a R11: 0000000000000000 R12: ffff8880a6cdeca0 R13: dffffc0000000000 R14: 1ffff11014d9bd94 R15: ffff8880984a75f8 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:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline] RIP: 0010:lock_is_held_type+0x25c/0x2b0 kernel/locking/lockdep.c:4524 Code: 68 95 2a 89 48 c1 e8 03 42 80 3c 30 00 74 0c 48 c7 c7 68 95 2a 89 e8 33 50 57 00 48 83 3d c3 be ce 07 00 74 56 4c 89 e7 57 9d <0f> 1f 44 00 00 89 d8 48 83 c4 28 5b 41 5c 41 5d 41 5e 41 5f 5d c3 RSP: 0018:ffffc90001da78b8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02 RAX: 1ffffffff12552ad RBX: 0000000000000000 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: ffff88809f206b88 RDI: 0000000000000286 RBP: ffffc90001da7908 R08: dffffc0000000000 R09: ffffed1012ae5577 R10: ffffed1012ae5577 R11: 0000000000000000 R12: 0000000000000286 R13: ffff88809f206b14 R14: dffffc0000000000 R15: 1ffff11013e40d62 lock_is_held include/linux/lockdep.h:361 [inline] ___might_sleep+0x3e/0x5e0 kernel/sched/core.c:6765 copy_pte_range mm/memory.c:853 [inline] copy_pmd_range mm/memory.c:892 [inline] copy_pud_range mm/memory.c:926 [inline] copy_p4d_range mm/memory.c:948 [inline] copy_page_range+0x249a/0x29a0 mm/memory.c:1010 dup_mmap+0xa01/0xe00 kernel/fork.c:604 dup_mm+0x9e/0x340 kernel/fork.c:1360 copy_mm kernel/fork.c:1416 [inline] copy_process+0x1e49/0x5510 kernel/fork.c:2072 _do_fork+0x13e/0x660 kernel/fork.c:2421 __do_sys_clone kernel/fork.c:2576 [inline] __se_sys_clone kernel/fork.c:2557 [inline] __x64_sys_clone+0x20b/0x250 kernel/fork.c:2557 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45951a Code: f7 d8 64 89 04 25 d4 02 00 00 64 4c 8b 0c 25 10 00 00 00 31 d2 4d 8d 91 d0 02 00 00 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 f5 00 00 00 85 c0 41 89 c5 0f 85 fc 00 00 RSP: 002b:00007ffe261c6260 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffe261c6260 RCX: 000000000045951a RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffe261c62a0 R08: 0000000000000001 R09: 00000000028cf940 R10: 00000000028cfc10 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffe261c62f0