syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=9ae/1/0x4000000000000002 softirq=13347/13347 fqs=2 
	(t=10500 jiffies g=6793 q=192)
rcu: rcu_preempt kthread starved for 10496 jiffies! g6793 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: 8578 Comm: syz-executor.4 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:mod_memcg_page_state+0x3d/0x190 include/linux/memcontrol.h:653
Code: 27 2e 00 48 83 c3 38 48 89 d8 48 c1 e8 03 49 bc 00 00 00 00 00 fc ff df 42 80 3c 20 00 74 08 48 89 df e8 e6 8f 6a 00 48 8b 1b <48> 85 db 0f 84 d8 00 00 00 48 c7 c0 60 95 2a 89 48 c1 e8 03 42 80
RSP: 0018:ffffc900023f7a18 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffffd400049b26f RBX: 0000000000000000 RCX: ffff88808c1e4040
RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00024d9340
RBP: ffffc900023f7a38 R08: 000000000003a728 R09: ffffed101233d6e9
R10: ffffed101233d6e9 R11: 0000000000000000 R12: dffffc0000000000
R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff8880919eb738
 free_thread_stack+0x168/0x590 kernel/fork.c:280
 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:arch_local_irq_restore arch/x86/include/asm/paravirt.h:752 [inline]
RIP: 0010:kfree+0x1a3/0x200 mm/slab.c:3758
Code: 48 83 3d 07 04 78 07 00 74 68 4c 89 f7 57 9d 0f 1f 44 00 00 eb 19 e8 3c d3 c9 ff 48 83 3d ec 03 78 07 00 74 51 4c 89 f7 57 9d <0f> 1f 44 00 00 5b 41 5c 41 5e 41 5f 5d c3 48 ff c9 48 89 c8 e9 c8
RSP: 0018:ffffc900023f7c90 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: ffff88808c1e48d4 RBX: ffff8880aa4001c0 RCX: ffff88808c1e4040
RDX: 0000000000000000 RSI: ffffffff8360d7a1 RDI: 0000000000000286
RBP: ffffc900023f7cb0 R08: ffff88808c1e4898 R09: ffffc900023f7a7c
R10: 0000000000000009 R11: 0000000000000000 R12: ffff888093aa3500
R13: dffffc0000000000 R14: 0000000000000286 R15: ffffffff8360d7a1
 tomoyo_path_number_perm+0x4e1/0x640 security/tomoyo/file.c:736
 tomoyo_file_ioctl+0x23/0x30 security/tomoyo/tomoyo.c:335
 security_file_ioctl+0x6d/0xd0 security/security.c:1409
 ksys_ioctl fs/ioctl.c:747 [inline]
 __do_sys_ioctl fs/ioctl.c:756 [inline]
 __se_sys_ioctl fs/ioctl.c:754 [inline]
 __x64_sys_ioctl+0xa3/0x120 fs/ioctl.c:754
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45adb7
Code: 48 83 c4 08 48 89 d8 5b 5d c3 66 0f 1f 84 00 00 00 00 00 48 89 e8 48 f7 d8 48 39 c3 0f 92 c0 eb 92 66 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 0d b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffe06ac068 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045adb7
RDX: 00007fffe06ac070 RSI: 0000000000008933 RDI: 0000000000000004
RBP: 00000000004c04a0 R08: 000000000000000a R09: 0000000000000008
R10: 0000000000000078 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000006 R15: 00007fffe06ac330