syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=2c2/1/0x4000000000000004 softirq=109779/109780 fqs=9 
	(t=10500 jiffies g=127753 q=221)
rcu: rcu_preempt kthread starved for 10480 jiffies! g127753 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29264    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3385 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4081
 schedule+0xdc/0x2b0 kernel/sched/core.c:4155
 schedule_timeout+0x486/0xc50 kernel/time/timer.c:1895
 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline]
 rcu_gp_kthread+0x9b2/0x18d0 kernel/rcu/tree.c:1821
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 0
CPU: 0 PID: 17147 Comm: syz-executor.4 Not tainted 5.5.0-rc7-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+0x197/0x210 lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x183/0x1cf 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.cold+0x509/0xc0d kernel/rcu/tree.c:2271
 update_process_times+0x2d/0x70 kernel/time/timer.c:1726
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:171
 tick_sched_timer+0x53/0x140 kernel/time/tick-sched.c:1314
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x364/0xe40 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0x160/0x610 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
RIP: 0010:lock_is_held_type+0xe/0x320 kernel/locking/lockdep.c:4510
Code: 48 89 75 d0 e8 43 8b 58 00 48 8b 75 d0 e9 1f fd ff ff 66 2e 0f 1f 84 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 55 48 89 e5 <41> 57 41 56 49 89 fe 41 55 41 54 65 4c 8b 24 25 c0 1e 02 00 49 8d
RSP: 0018:ffffc90000007c88 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: 1ffff92000000f93 RCX: 0000000000000000
RDX: 0000000000000101 RSI: 00000000ffffffff RDI: ffffffff899a3d40
RBP: ffffc90000007c88 R08: ffff888047e0c180 R09: ffffed1015d0703d
R10: ffffed1015d0703c R11: ffff8880ae8381e3 R12: 0000000000000100
R13: ffffc90000007db0 R14: 0000000000000000 R15: dffffc0000000000
 lock_is_held include/linux/lockdep.h:361 [inline]
 rcu_read_lock_sched_held+0x9c/0xd0 kernel/rcu/update.c:122
 trace_timer_expire_entry include/trace/events/timer.h:90 [inline]
 call_timer_fn+0x6de/0x780 kernel/time/timer.c:1403
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers kernel/time/timer.c:1773 [inline]
 __run_timers kernel/time/timer.c:1740 [inline]
 run_timer_softirq+0x6c3/0x1790 kernel/time/timer.c:1786
 __do_softirq+0x262/0x98c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:373 [inline]
 irq_exit+0x19b/0x1e0 kernel/softirq.c:413
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x1a3/0x610 arch/x86/kernel/apic/apic.c:1137
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:__read_once_size include/linux/compiler.h:199 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x38/0x50 kernel/kcov.c:192
Code: 8b 15 14 27 8d 7e 81 e2 00 01 1f 00 48 8b 75 08 75 2b 8b 90 80 13 00 00 83 fa 02 75 20 48 8b 88 88 13 00 00 8b 80 84 13 00 00 <48> 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f
RSP: 0018:ffffc90007e6fac0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000040000 RBX: ffff88809f85b000 RCX: ffffc90011fe1000
RDX: 0000000000000002 RSI: ffffffff8362f4ef RDI: 0000000000000001
RBP: ffffc90007e6fac0 R08: ffff888047e0c180 R09: ffffc90007e6fb88
R10: fffff52000fcdf7a R11: ffffc90007e6fbd7 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffc90007e6fb88 R15: 0000000000000005
 tomoyo_check_acl+0xdf/0x3e0 security/tomoyo/domain.c:173
 tomoyo_inet_entry security/tomoyo/network.c:483 [inline]
 tomoyo_check_inet_address security/tomoyo/network.c:532 [inline]
 tomoyo_check_inet_address+0x622/0x730 security/tomoyo/network.c:501
 tomoyo_socket_connect_permission+0x26b/0x380 security/tomoyo/network.c:710
 tomoyo_socket_connect+0x26/0x30 security/tomoyo/tomoyo.c:456
 security_socket_connect+0x77/0xc0 security/security.c:1998
 __sys_connect_file+0xae/0x1c0 net/socket.c:1840
 __sys_connect+0x174/0x1b0 net/socket.c:1861
 __do_sys_connect net/socket.c:1872 [inline]
 __se_sys_connect net/socket.c:1869 [inline]
 __x64_sys_connect+0x73/0xb0 net/socket.c:1869
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45b349
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:00007fae9ceb1c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007fae9ceb26d4 RCX: 000000000045b349
RDX: 0000000000000010 RSI: 0000000020004cc0 RDI: 0000000000000005
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000007d R14: 00000000004c1c5b R15: 000000000075bf2c