rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (10499 ticks this GP) idle=e46/1/0x4000000000000002 softirq=10359/10359 fqs=1 (t=10500 jiffies g=6229 q=179) rcu: rcu_preempt kthread starved for 10498 jiffies! g6229 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29104 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: 8135 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+0x16d/0x590 kernel/fork.c:284 Code: c3 08 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 25 a0 69 00 48 8b 3b be fc ff 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 RSP: 0018:ffffc900023c7990 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81487433 RBX: ffff8880a0444e08 RCX: ffff88809484e680 RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea0002a15440 RBP: ffffc900023c79c8 R08: dffffc0000000000 R09: fffffbfff120248a R10: fffffbfff120248a R11: 0000000000000000 R12: ffff8880a0444ea0 R13: dffffc0000000000 R14: 1ffff110140889d4 R15: ffff888097d7b868 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_notrace+0xdb/0x120 kernel/sched/core.c:4309 ___preempt_schedule_notrace+0x16/0x27 arch/x86/entry/thunk_64.S:51 rcu_read_unlock_sched_notrace include/linux/rcupdate.h:755 [inline] trace_kfree+0xf5/0x110 include/trace/events/kmem.h:138 kfree+0x1d/0x200 mm/slab.c:3743 __vunmap+0x9fe/0xa90 mm/vmalloc.c:2315 __vfree mm/vmalloc.c:2356 [inline] vfree+0x85/0x130 mm/vmalloc.c:2386 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:883 [inline] get_entries net/ipv6/netfilter/ip6_tables.c:1041 [inline] do_ip6t_get_ctl+0x79c/0x9b0 net/ipv6/netfilter/ip6_tables.c:1709 nf_sockopt net/netfilter/nf_sockopt.c:104 [inline] nf_getsockopt+0x287/0x2b0 net/netfilter/nf_sockopt.c:122 ipv6_getsockopt+0x1c3/0x2c0 net/ipv6/ipv6_sockglue.c:1400 tcp_getsockopt+0xbe/0xd0 net/ipv4/tcp.c:3692 sock_common_getsockopt+0x99/0xb0 net/core/sock.c:3108 __sys_getsockopt+0x24c/0x2b0 net/socket.c:2162 __do_sys_getsockopt net/socket.c:2177 [inline] __se_sys_getsockopt net/socket.c:2174 [inline] __x64_sys_getsockopt+0xbf/0xd0 net/socket.c:2174 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45d18a Code: b8 34 01 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 8d 8b fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 37 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 6a 8b fb ff c3 66 0f 1f 84 00 00 00 00 00 RSP: 002b:00007ffd51d7c3e8 EFLAGS: 00000212 ORIG_RAX: 0000000000000037 RAX: ffffffffffffffda RBX: 00007ffd51d7c410 RCX: 000000000045d18a RDX: 0000000000000041 RSI: 0000000000000029 RDI: 0000000000000003 RBP: 0000000000717cc0 R08: 00007ffd51d7c40c R09: 0000000000004000 R10: 00007ffd51d7c510 R11: 0000000000000212 R12: 0000000000000003 R13: 0000000000000000 R14: 0000000000000029 R15: 0000000000716880