syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10499 ticks this GP) idle=1ea/1/0x4000000000000002 softirq=13552/13552 fqs=3 
	(t=10500 jiffies g=6845 q=238)
rcu: rcu_preempt kthread starved for 10494 jiffies! g6845 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    28984    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 1
CPU: 1 PID: 8458 Comm: udevd 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+0x168/0x190 include/linux/memcontrol.h:655
Code: c7 68 95 2a 89 e8 d8 8e 6a 00 48 83 3d 68 fd e1 07 00 74 2d e8 79 26 2e 00 4c 89 ff 57 9d 0f 1f 44 00 00 5b 41 5c 41 5e 41 5f <5d> c3 e8 61 26 2e 00 0f 0b e8 5a 26 2e 00 0f 0b e8 53 26 2e 00 0f
RSP: 0018:ffffc90001e07458 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: ffffffff814897d3 RBX: ffff8880a2073b88 RCX: ffff88809f754080
RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00028976c0
RBP: ffffc90001e07458 R08: dffffc0000000000 R09: fffffbfff124248a
R10: fffffbfff124248a R11: 0000000000000000 R12: ffff8880a2073c20
R13: dffffc0000000000 R14: 1ffff1101440e784 R15: ffff8880a861d6f8
 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:preempt_count arch/x86/include/asm/preempt.h:26 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:153 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:208 [inline]
RIP: 0010:__sanitizer_cov_trace_switch+0x65/0x100 kernel/kcov.c:310
Code: 00 00 00 4c 8b 04 c5 f0 6f 64 88 4c 8b 4c 24 20 65 4c 8b 14 25 c0 1d 02 00 31 d2 66 2e 0f 1f 84 00 00 00 00 00 4c 8b 74 d6 10 <65> 8b 05 30 5a 8b 7e a9 00 01 1f 00 75 6d 41 8b 82 80 13 00 00 83
RSP: 0018:ffffc90001e076b8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff02
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000006 RSI: ffffffff893fadc0 RDI: 0000000000000000
RBP: ffffc90001e07720 R08: 0000000000000001 R09: ffffffff83621d45
R10: ffff88809f754080 R11: 0000000000000007 R12: ffff88809e4a0380
R13: ffff888093786910 R14: 0000000000000008 R15: dffffc0000000000
 tomoyo_supervisor+0x274/0x1330 security/tomoyo/common.c:2089
 tomoyo_audit_path_log security/tomoyo/file.c:168 [inline]
 tomoyo_path_permission security/tomoyo/file.c:587 [inline]
 tomoyo_check_open_permission+0x723/0x9d0 security/tomoyo/file.c:780
 tomoyo_file_open+0x141/0x190 security/tomoyo/tomoyo.c:319
 security_file_open+0x65/0x2f0 security/security.c:1497
 do_dentry_open+0x351/0x10c0 fs/open.c:784
 vfs_open+0x73/0x80 fs/open.c:914
 do_last fs/namei.c:3420 [inline]
 path_openat+0x1387/0x4240 fs/namei.c:3537
 do_filp_open+0x192/0x3d0 fs/namei.c:3567
 do_sys_open+0x29f/0x560 fs/open.c:1097
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x87/0x90 fs/open.c:1110
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f07ffc75120
Code: 48 8b 15 1b 4d 2b 00 f7 d8 64 89 02 83 c8 ff c3 90 90 90 90 90 90 90 90 90 90 83 3d d5 a4 2b 00 00 75 10 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 5e 8c 01 00 48 89 04 24
RSP: 002b:00007fff6a2b7bf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000c6bf40 RCX: 00007f07ffc75120
RDX: 00000000000001b6 RSI: 0000000000080241 RDI: 00007fff6a2b80e0
RBP: 00007fff6a2b7c70 R08: 0000000000000004 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000004
R13: 0000000000420721 R14: 00007fff6a2b7ce0 R15: 0000000000000000