rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10499 ticks this GP) idle=9fa/1/0x4000000000000002 softirq=10713/10713 fqs=41 
	(t=10501 jiffies g=6373 q=93)
rcu: rcu_preempt kthread starved for 10420 jiffies! g6373 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
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 1
CPU: 1 PID: 8235 Comm: syz-executor.2 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:1514 [inline]
 __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576
 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638
 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:__sanitizer_cov_trace_pc+0x0/0x50 kernel/kcov.c:98
Code: 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 53 48 89 fb e8 13 00 00 00 48 8b 3d 34 e7 cc 07 48 89 de e8 64 02 3b 00 5b 5d c3 cc <48> 8b 04 24 65 48 8b 0c 25 c0 1d 02 00 65 8b 15 b8 81 8b 7e f7 c2
RSP: 0018:ffffc9000200f8a0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffffd400045c3c7 RBX: 0000000000000000 RCX: ffff888094e60040
RDX: 0000000000000000 RSI: 00000000fffffffc RDI: ffffea00022e1e00
RBP: ffffc9000200f8c8 R08: 000000000003a768 R09: ffffed10134766b7
R10: ffffed10134766b7 R11: 0000000000000000 R12: dffffc0000000000
R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff88809a3b35a8
 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:vsnprintf+0x14b/0x1c00 lib/vsprintf.c:2530
Code: c8 48 89 45 98 44 0f b6 e0 4c 89 e7 48 c7 c6 20 b2 3d 89 e8 27 e7 95 f9 41 80 fc 12 0f 87 ff 08 00 00 42 ff 24 e5 30 3a 7d 88 <4c> 8b 65 b8 4d 39 e6 0f 83 f6 0b 00 00 e8 53 e2 95 f9 4d 29 f4 4c
RSP: 0018:ffffc9000200fb20 EFLAGS: 00000297 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000000000
RDX: 0000000000000012 RSI: ffffffff893db220 RDI: 0000000000000000
RBP: ffffc9000200fba0 R08: 0000000000000001 R09: ffffffff87e0b989
R10: ffff888094e60040 R11: 0000000000000012 R12: 0000000000000000
R13: ffffffff88c7d2df R14: ffff8880994ac010 R15: ffffffff88c7d2e5
 snprintf+0x6f/0x90 lib/vsprintf.c:2707
 tomoyo_get_socket_name security/tomoyo/realpath.c:237 [inline]
 tomoyo_realpath_from_path+0x235/0x7c0 security/tomoyo/realpath.c:284
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_number_perm+0x166/0x640 security/tomoyo/file.c:723
 tomoyo_file_ioctl+0x23/0x30 security/tomoyo/tomoyo.c:335
 security_file_ioctl+0x6d/0xd0 security/security.c:1409
 ksys_ioctl fs/ioctl.c:741 [inline]
 __do_sys_ioctl fs/ioctl.c:750 [inline]
 __se_sys_ioctl fs/ioctl.c:748 [inline]
 __x64_sys_ioctl+0xa3/0x120 fs/ioctl.c:748
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a4e7
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:00007ffedb1e08b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a4e7
RDX: 00007ffedb1e08c0 RSI: 0000000000008933 RDI: 0000000000000004
RBP: 00000000004bfb97 R08: 0000000000000008 R09: 000000000000000a
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000006 R14: 0000000000000000 R15: 00007ffedb1e0b40