syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=082/1/0x4000000000000002 softirq=12662/12662 fqs=6 
	(t=10500 jiffies g=6785 q=206)
rcu: rcu_preempt kthread starved for 10487 jiffies! g6785 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I28984    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: 8472 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:
 <IRQ>
 __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
 </IRQ>
RIP: 0010:free_thread_stack+0x133/0x590 kernel/fork.c:280
Code: 00 ea ff ff 48 01 c7 be 03 00 00 00 e8 86 91 61 00 e9 5d 04 00 00 e8 3c 2c 2e 00 48 89 df 31 f6 e8 02 8d 6f 00 43 80 3c 2e 00 <74> 08 4c 89 e7 e8 73 94 6a 00 49 8b 1c 24 48 83 c3 08 48 89 d8 48
RSP: 0018:ffffc90001e274b8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000001 RBX: ffffea0002788280 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea0002788280
RBP: ffffc90001e274f0 R08: 000000000003a728 R09: fffffbfff124248a
R10: fffffbfff124248a R11: 0000000000000000 R12: ffff8880a6fc31a0
R13: dffffc0000000000 R14: 1ffff11014df8634 R15: ffff8880949056b8
 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:stack_trace_consume_entry+0x70/0x260 kernel/stacktrace.c:86
Code: 74 24 10 49 8d 5c 24 08 48 89 d8 48 c1 e8 03 48 89 45 b8 42 8a 04 38 84 c0 0f 85 4d 01 00 00 48 89 5d c0 8b 1b 44 89 f7 89 de <e8> fb fd 10 00 4c 89 f0 39 d8 73 59 49 8d 54 24 0c 48 89 d3 48 c1
RSP: 0018:ffffc90001e27700 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffff920003c4f00 RBX: 0000000000000040 RCX: ffff88807dcc6440
RDX: 0000000000000000 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffffc90001e27750 R08: ffffffff8165c225 R09: ffffc90001e27760
R10: fffff520003c4ef8 R11: 0000000000000000 R12: ffffc90001e27800
R13: 1ffff920003c4f02 R14: 0000000000000000 R15: dffffc0000000000
 arch_stack_walk+0xa8/0xe0 arch/x86/kernel/stacktrace.c:27
 stack_trace_save+0xb6/0x150 kernel/stacktrace.c:123
 save_stack mm/kasan/common.c:72 [inline]
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc+0x11c/0x1b0 mm/kasan/common.c:513
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:527
 __do_kmalloc_node mm/slab.c:3616 [inline]
 __kmalloc_node+0x4d/0x60 mm/slab.c:3623
 kmalloc_node include/linux/slab.h:579 [inline]
 __vmalloc_area_node mm/vmalloc.c:2466 [inline]
 __vmalloc_node_range+0x2ba/0x850 mm/vmalloc.c:2546
 __vmalloc_node mm/vmalloc.c:2601 [inline]
 __vmalloc_node_flags mm/vmalloc.c:2615 [inline]
 vzalloc+0x73/0x80 mm/vmalloc.c:2660
 alloc_counters+0x6b/0x6e0 net/ipv6/netfilter/ip6_tables.c:816
 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:838 [inline]
 get_entries net/ipv6/netfilter/ip6_tables.c:1041 [inline]
 do_ip6t_get_ctl+0x4a6/0x9b0 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:3690
 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: 0033:0x45da5a
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:00007ffe2dc3b568 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045da5a
RDX: 0000000000000041 RSI: 0000000000000029 RDI: 0000000000000003
RBP: 0000000000000029 R08: 00007ffe2dc3b58c R09: 0000000000000358
R10: 00007ffe2dc3b590 R11: 0000000000000246 R12: 00000000004c811b
R13: 0000000000719cc0 R14: 0000000000000358 R15: 0000000000719600