rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10499 ticks this GP) idle=86e/1/0x4000000000000002 softirq=11958/11958 fqs=39 (t=10501 jiffies g=6345 q=105) rcu: rcu_preempt kthread starved for 10424 jiffies! g6345 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29048 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: 8274 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: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 09 a0 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 eb 9f 69 00 48 8b 1b e9 82 ff ff ff e8 5e 2a 2e RSP: 0018:ffffc90001f576c8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff11012116bb1 RBX: ffff8880908b5d88 RCX: ffff888094a3a000 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00025c9f80 RBP: ffffc90001f57700 R08: 000000000003a728 R09: ffffed10140abf17 R10: ffffed10140abf17 R11: 0000000000000000 R12: ffff8880908b5e20 R13: dffffc0000000000 R14: 1ffff11012116bc4 R15: ffff8880a055f8a8 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 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x46/0x240 kernel/time/timer.c:1871 do_wait_for_common+0x2e7/0x4d0 kernel/sched/completion.c:83 __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x47/0x60 kernel/sched/completion.c:136 __wait_rcu_gp+0x2b1/0x2f0 kernel/rcu/update.c:374 synchronize_rcu+0xe3/0x100 kernel/rcu/tree.c:2768 rcu_sync_enter+0x1ae/0x2a0 kernel/rcu/sync.c:149 percpu_down_write+0x30/0x3c0 kernel/locking/percpu-rwsem.c:146 cpuset_css_online+0x59/0x7e0 kernel/cgroup/cpuset.c:2733 online_css+0xbb/0x230 kernel/cgroup/cgroup.c:5047 css_create kernel/cgroup/cgroup.c:5118 [inline] cgroup_apply_control_enable+0xd46/0x1240 kernel/cgroup/cgroup.c:3064 cgroup_mkdir+0xeb8/0x1280 kernel/cgroup/cgroup.c:5327 kernfs_iop_mkdir+0x133/0x270 fs/kernfs/dir.c:1127 vfs_mkdir+0x43f/0x610 fs/namei.c:3811 do_mkdirat+0x1d7/0x320 fs/namei.c:3834 __do_sys_mkdir fs/namei.c:3850 [inline] __se_sys_mkdir fs/namei.c:3848 [inline] __x64_sys_mkdir+0x60/0x70 fs/namei.c:3848 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x459a97 Code: 1f 40 00 b8 5a 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 7d c2 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 5d c2 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffecca3d9c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000459a97 RDX: 00007ffecca3da23 RSI: 00000000000001ff RDI: 00007ffecca3da10 RBP: 00000000000000f8 R08: 0000000000000000 R09: 0000000000000013 R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000416180 R13: 00007ffecca3de38 R14: 0000000000000000 R15: 00007ffecca3da10