rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10499 ticks this GP) idle=14e/1/0x4000000000000002 softirq=11521/11521 fqs=0 
	(t=10500 jiffies g=6457 q=70)
rcu: rcu_preempt kthread starved for 10500 jiffies! g6457 f0x0 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
NMI backtrace for cpu 1
CPU: 1 PID: 8204 Comm: syz-executor.0 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:free_thread_stack+0x133/0x590 kernel/fork.c:280
Code: 00 ea ff ff 48 01 c7 be 03 00 00 00 e8 06 a2 60 00 e9 5d 04 00 00 e8 5c 2d 2e 00 48 89 df 31 f6 e8 42 af 6e 00 43 80 3c 2e 00 <74> 08 4c 89 e7 e8 43 a4 69 00 49 8b 1c 24 48 83 c3 08 48 89 d8 48
RSP: 0018:ffffc900024574b0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000001 RBX: ffffea00022e50c0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea00022e50c0
RBP: ffffc900024574e8 R08: 000000000003a768 R09: fffffbfff120248a
R10: fffffbfff120248a R11: 0000000000000000 R12: ffff8880a9600020
R13: dffffc0000000000 R14: 1ffff110152c0004 R15: ffff8880921b74a8
 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_notrace+0xdb/0x120 kernel/sched/core.c:4309
 ___preempt_schedule_notrace+0x16/0x27 arch/x86/entry/thunk_64.S:51
 rcu_is_watching+0x82/0xa0 kernel/rcu/tree.c:923
 rcu_read_unlock include/linux/rcupdate.h:667 [inline]
 memcg_kmem_get_cache+0x301/0x590 mm/memcontrol.c:2808
 slab_pre_alloc_hook mm/slab.h:572 [inline]
 slab_alloc mm/slab.c:3306 [inline]
 kmem_cache_alloc+0x86/0x2e0 mm/slab.c:3484
 proc_alloc_inode+0x1f/0xe0 fs/proc/inode.c:62
 alloc_inode fs/inode.c:230 [inline]
 new_inode_pseudo+0x68/0x240 fs/inode.c:919
 new_inode+0x28/0x1c0 fs/inode.c:948
 proc_pid_make_inode+0x27/0x1d0 fs/proc/base.c:1754
 proc_pid_instantiate+0x4f/0x1a0 fs/proc/base.c:3227
 proc_pid_lookup+0x21f/0x300 fs/proc/base.c:3262
 proc_root_lookup+0x22/0x50 fs/proc/root.c:248
 __lookup_slow+0x285/0x380 fs/namei.c:1667
 lookup_slow fs/namei.c:1684 [inline]
 walk_component+0x2d6/0x7b0 fs/namei.c:1804
 link_path_walk+0x75b/0x1410 fs/namei.c:2121
 path_openat+0x139/0x44a0 fs/namei.c:3528
 do_filp_open+0x192/0x3d0 fs/namei.c:3559
 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: 0033:0x4143f0
Code: 05 48 3d 01 f0 ff ff 0f 83 2d 19 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 3d 7d 40 66 00 00 75 14 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48 83 ec 08 e8 0a fa ff ff
RSP: 002b:00007ffd07d07d08 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007ffd07d07d34 RCX: 00000000004143f0
RDX: 00007ffd07d07d3a RSI: 0000000000080001 RDI: 00000000004c00fb
RBP: 00007ffd07d07d30 R08: 0000000000000000 R09: 0000000000000004
R10: 0000000000000075 R11: 0000000000000246 R12: 00000000004c00fb
R13: 00007ffd07d08250 R14: 0000000000000000 R15: 00007ffd07d08260