rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=772/1/0x4000000000000002 softirq=11830/11830 fqs=41 (t=10501 jiffies g=6069 q=399) rcu: rcu_preempt kthread starved for 10418 jiffies! g6069 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: 8169 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:mod_memcg_page_state+0x0/0x190 include/linux/memcontrol.h:652 Code: 48 8b 3b e8 12 c1 5f 00 eb 0c e8 0b 29 2e 00 eb 05 e8 04 29 2e 00 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 1f 44 00 00 <55> 48 89 e5 41 57 41 56 41 54 53 41 89 f6 48 89 fb e8 da 28 2e 00 RSP: 0018:ffffc900024f77a8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: 1ffff11011e81c61 RBX: ffff88808f40e308 RCX: 0000000000000000 RDX: ffffc90002079000 RSI: 00000000fffffffc RDI: ffffea00026bbf80 RBP: ffffc900024f77e8 R08: 000000000003a768 R09: ffffed10141eb687 R10: ffffed10141eb687 R11: 0000000000000000 R12: ffff88808f40e3a0 R13: dffffc0000000000 R14: 1ffff11011e81c74 R15: ffff8880a0f5b428 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 vprintk_emit+0x36d/0x3a0 kernel/printk/printk.c:1997 vprintk_default+0x28/0x30 kernel/printk/printk.c:2023 vprintk_func+0x158/0x170 kernel/printk/printk_safe.c:386 printk+0x62/0x8d kernel/printk/printk.c:2056 kobject_add_internal+0x22a/0xc20 lib/kobject.c:250 kobject_add_varg lib/kobject.c:390 [inline] kobject_init_and_add+0xb7/0x100 lib/kobject.c:473 nfs_netns_client_alloc fs/nfs/sysfs.c:158 [inline] nfs_netns_sysfs_setup+0xe4/0x150 fs/nfs/sysfs.c:170 nfs_clients_init+0x173/0x1c0 fs/nfs/client.c:1080 nfs_net_init+0x15/0x20 fs/nfs/inode.c:2172 ops_init+0x355/0x430 net/core/net_namespace.c:137 setup_net+0x1f0/0x7c0 net/core/net_namespace.c:335 copy_net_ns+0x334/0x540 net/core/net_namespace.c:476 create_new_namespaces+0x4c3/0x770 kernel/nsproxy.c:103 unshare_nsproxy_namespaces+0x12a/0x190 kernel/nsproxy.c:202 ksys_unshare+0x478/0xa00 kernel/fork.c:2935 __do_sys_unshare kernel/fork.c:3003 [inline] __se_sys_unshare kernel/fork.c:3001 [inline] __x64_sys_unshare+0x38/0x40 kernel/fork.c:3001 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a679 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:00007fadc2eb5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 000000000045a679 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000006c060000 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fadc2eb66d4 R13: 00000000004cb0d0 R14: 00000000004e47b0 R15: 00000000ffffffff