syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=6797, q=160)
rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294953755-4294943252), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor.0  R  running task    26376  8413   8394 0x0000400e
Call Trace:
 <IRQ>
 sched_show_task+0x40f/0x560 kernel/sched/core.c:5954
 print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:538 [inline]
 rcu_pending kernel/rcu/tree.c:2827 [inline]
 rcu_sched_clock_irq+0x1861/0x1ad0 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:__read_once_size include/linux/compiler.h:199 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x2e/0x50 kernel/kcov.c:192
Code: 65 48 8b 0c 25 c0 1d 02 00 65 8b 15 38 5f 8b 7e f7 c2 00 01 1f 00 75 2c 8b 91 80 13 00 00 83 fa 02 75 21 48 8b 91 88 13 00 00 <48> 8b 32 48 8d 7e 01 8b 89 84 13 00 00 48 39 cf 73 08 48 89 44 f2
RSP: 0018:ffffc90002287728 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffffff81489244 RBX: ffffea00025f7780 RCX: ffff888090282040
RDX: ffffc90001f59000 RSI: 000000000003ffff RDI: 0000000000040000
RBP: ffffc90002287768 R08: dffffc0000000000 R09: fffffbfff12c962d
R10: fffffbfff12c962d R11: 0000000000000000 R12: ffff88809faaf1a0
R13: dffffc0000000000 R14: 1ffff11013f55e34 R15: ffff888097b1d738
 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
 schedule+0x181/0x210 kernel/sched/core.c:4155
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214
 __mutex_lock_common+0x1411/0x2e10 kernel/locking/mutex.c:1033
 __mutex_lock kernel/locking/mutex.c:1103 [inline]
 mutex_lock_interruptible_nested+0x1b/0x30 kernel/locking/mutex.c:1140
 tomoyo_get_name+0x47/0x540 security/tomoyo/memory.c:164
 tomoyo_parse_name_union+0x169/0x1f0 security/tomoyo/util.c:258
 tomoyo_update_path_number_acl security/tomoyo/file.c:687 [inline]
 tomoyo_write_file+0x756/0x1040 security/tomoyo/file.c:1034
 tomoyo_write_domain2 security/tomoyo/common.c:1152 [inline]
 tomoyo_add_entry security/tomoyo/common.c:2042 [inline]
 tomoyo_supervisor+0x1021/0x1330 security/tomoyo/common.c:2103
 tomoyo_audit_path_number_log security/tomoyo/file.c:235 [inline]
 tomoyo_path_number_perm+0x471/0x640 security/tomoyo/file.c:734
 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: 0033:0x45af49
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:00007fd904244c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045af49
RDX: 0000000000400200 RSI: 0000000000008912 RDI: 0000000000000005
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd9042456d4
R13: 00000000004c4f66 R14: 00000000004db980 R15: 00000000ffffffff
rcu: rcu_preempt kthread starved for 10537 jiffies! g6797 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29032    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