syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=6f2/1/0x4000000000000002 softirq=10325/10325 fqs=0 
	(t=10501 jiffies g=5973 q=69)
rcu: rcu_preempt kthread starved for 10502 jiffies! g5973 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: 8116 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:
 <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+0x182/0x590 kernel/fork.c:284
Code: 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> c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 eb 9f 69 00 48 8b 1b
RSP: 0018:ffffc900023f72e8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: ffff8880a467e608 RBX: ffff8880a467e608 RCX: 0000000000040000
RDX: ffffc90001f29000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc900023f7320 R08: 000000000003a728 R09: fffffbfff120248a
R10: fffffbfff120248a R11: 0000000000000000 R12: ffff8880a467e6a0
R13: dffffc0000000000 R14: 1ffff110148cfcd4 R15: ffff8880a01ef3e8
 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:bpf_verifier_vlog+0x2e/0x2f0 kernel/bpf/verifier.c:267
Code: 41 57 41 56 41 55 41 54 53 48 83 ec 18 49 89 d7 48 89 f3 49 89 fe e8 51 2c f3 ff 4d 8d 66 04 be 00 04 00 00 4c 89 e7 48 89 da <4c> 89 f9 e8 6a 7c 6a 06 41 89 c5 bf fe 03 00 00 89 c6 e8 cb 2f f3
RSP: 0018:ffffc900023f7530 EFLAGS: 00000287 ORIG_RAX: ffffffffffffff02
RAX: ffffffff81836d2f RBX: ffffffff88bee161 RCX: 0000000000040000
RDX: ffffffff88bee161 RSI: 0000000000000400 RDI: ffff888093d20264
RBP: ffffc900023f7570 R08: ffffffff81847194 R09: ffffffff8186649f
R10: ffff8880a458a040 R11: 0000000000000002 R12: ffff888093d20264
R13: ffffffff88bee161 R14: ffff888093d20260 R15: ffffc900023f75c0
 verbose+0x173/0x200 kernel/bpf/verifier.c:312
 check_reg_arg+0x42c/0xb20 kernel/bpf/verifier.c:1443
 check_func_arg kernel/bpf/verifier.c:3415 [inline]
 check_helper_call kernel/bpf/verifier.c:4227 [inline]
 do_check+0x90f4/0x1c4d0 kernel/bpf/verifier.c:7967
 bpf_check+0xd9a8/0xfc40 kernel/bpf/verifier.c:9772
 bpf_prog_load kernel/bpf/syscall.c:1805 [inline]
 __do_sys_bpf+0x99d6/0xc890 kernel/bpf/syscall.c:3030
 __se_sys_bpf kernel/bpf/syscall.c:2989 [inline]
 __x64_sys_bpf+0x7a/0x90 kernel/bpf/syscall.c:2989
 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:00007f83b5719c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a679
RDX: 0000000000000070 RSI: 00000000200006c0 RDI: 0000000000000005
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f83b571a6d4
R13: 00000000004c0d07 R14: 00000000004d4828 R15: 00000000ffffffff