rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (1 ticks this GP) idle=cc6/1/0x4000000000000000 softirq=9240/9240 fqs=0 
	(t=24804 jiffies g=4157 q=299)
rcu: rcu_preempt kthread starved for 24804 jiffies! g4157 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    14512    10      2 0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x3f3/0x880 kernel/sched/core.c:4527
 schedule+0x37/0xe0 kernel/sched/core.c:4602
 schedule_timeout+0x1af/0x2d0 kernel/time/timer.c:1879
 rcu_gp_fqs_loop kernel/rcu/tree.c:1887 [inline]
 rcu_gp_kthread+0x707/0xc60 kernel/rcu/tree.c:2057
 kthread+0x148/0x170 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
NMI backtrace for cpu 1
CPU: 1 PID: 6413 Comm: in:imklog Not tainted 5.8.0-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+0xb3/0xec lib/dump_stack.c:118
 nmi_cpu_backtrace.cold.8+0x3e/0x58 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0xd5/0xec lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0xa2/0xce kernel/rcu/tree_stall.h:318
 print_cpu_stall kernel/rcu/tree_stall.h:551 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:625 [inline]
 rcu_pending kernel/rcu/tree.c:3635 [inline]
 rcu_sched_clock_irq.cold.93+0x61/0x52d kernel/rcu/tree.c:2518
 update_process_times+0x1f/0x60 kernel/time/timer.c:1710
 tick_sched_handle.isra.20+0x1a/0x50 kernel/time/tick-sched.c:176
 tick_sched_timer+0x6c/0x80 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x1e1/0x510 kernel/time/hrtimer.c:1584
 hrtimer_interrupt+0xf9/0x210 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x8e/0x2b0 arch/x86/kernel/apic/apic.c:1097
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_apic_timer_interrupt+0xc1/0xe0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581
RIP: 0010:__virt_addr_valid+0x0/0xb0 arch/x86/mm/physaddr.c:49
Code: c7 c6 f8 0d 62 83 c6 05 74 85 4e 03 01 48 c7 c7 68 5d e4 83 e8 ba 47 15 00 31 c0 e9 ff fb ff ff cc cc cc cc cc cc cc cc cc cc <b8> 00 00 00 80 48 01 f8 48 89 c2 0f 82 87 00 00 00 48 b8 00 00 00
RSP: 0018:ffffc90000f4be00 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff88810f829000 RCX: 0000000000000006
RDX: ffffc90000f4c000 RSI: ffff88810f829071 RDI: ffff88810f829000
RBP: 0000000000000071 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000036333936 R11: 0000000033393654 R12: 0000000000000001
R13: ffff88810f829071 R14: 0000000000000071 R15: 00007f7f8cb7dda0
 check_heap_object mm/usercopy.c:228 [inline]
 __check_object_size+0x52/0x1a3 mm/usercopy.c:286
 check_object_size include/linux/thread_info.h:119 [inline]
 check_copy_size include/linux/thread_info.h:152 [inline]
 copy_to_user include/linux/uaccess.h:151 [inline]
 syslog_print kernel/printk/printk.c:1440 [inline]
 do_syslog+0x6ad/0x980 kernel/printk/printk.c:1565
 kmsg_read+0x3c/0x50 fs/proc/kmsg.c:40
 vfs_read+0xa8/0x1b0 fs/read_write.c:479
 ksys_read+0x5a/0xd0 fs/read_write.c:607
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f7f8f1e122d
Code: c1 20 00 00 75 10 b8 00 00 00 00 0f 05 48 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 4e fc ff ff 48 89 04 24 b8 00 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 97 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007f7f8cb7d580 EFLAGS: 00000293 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7f8f1e122d
RDX: 0000000000001fa0 RSI: 00007f7f8cb7dda0 RDI: 0000000000000004
RBP: 000055f3963599d0 R08: 0000000000000000 R09: 0000000004000001
R10: 0000000000000001 R11: 0000000000000293 R12: 00007f7f8cb7dda0
R13: 0000000000001fa0 R14: 0000000000001f9f R15: 00007f7f8cb7de18