rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=af2/1/0x4000000000000002 softirq=13167/13167 fqs=40 
	(t=10501 jiffies g=6581 q=147)
rcu: rcu_preempt kthread starved for 10422 jiffies! g6581 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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 0
CPU: 0 PID: 8407 Comm: syz-executor.5 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:check_kcov_mode kernel/kcov.c:153 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x14/0x50 kernel/kcov.c:187
Code: 00 00 00 48 8b 3d f4 f4 ed 07 48 89 de e8 84 f4 3b 00 5b 5d c3 cc 48 8b 04 24 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
RSP: 0018:ffffc90002427a20 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffffffff814897d3 RBX: 0000000000000000 RCX: ffff88809c45c180
RDX: 0000000000000001 RSI: 00000000fffffffc RDI: ffffea00023ee680
RBP: ffffc90002427a48 R08: 000000000003a728 R09: fffffbfff124248a
R10: fffffbfff124248a R11: 0000000000000000 R12: dffffc0000000000
R13: dffffc0000000000 R14: 00000000fffffffc R15: ffff888096a99938
 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:__fs_reclaim_acquire+0x1/0x30 mm/page_alloc.c:4083
Code: ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 55 ff ff ff 48 89 df e8 6f bc 08 00 e9 48 ff ff ff e8 65 62 9e ff 0f 1f 44 00 00 55 <48> 89 e5 48 c7 c7 90 e9 2f 89 31 f6 31 d2 31 c9 41 b8 01 00 00 00
RSP: 0018:ffffc90002427ca0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000000 RBX: ffff88809c45c1a4 RCX: dffffc0000000000
RDX: 0000000000000000 RSI: 0000000000000dc0 RDI: 0000000000000dc0
RBP: ffffc90002427cc0 R08: ffffffff81bd45c2 R09: ffffed1012c0056a
R10: ffffed1012c0056a R11: 0000000000000000 R12: ffff88821bc4e700
R13: 1ffff92000484fc2 R14: 0000000000000000 R15: 0000000000000dc0
 slab_pre_alloc_hook mm/slab.h:562 [inline]
 slab_alloc mm/slab.c:3306 [inline]
 kmem_cache_alloc+0x2a/0x2e0 mm/slab.c:3484
 kmem_cache_zalloc include/linux/slab.h:660 [inline]
 __alloc_file+0x2c/0x390 fs/file_table.c:101
 alloc_empty_file+0xac/0x1b0 fs/file_table.c:151
 alloc_file+0x60/0x4c0 fs/file_table.c:193
 alloc_file_pseudo+0x1d4/0x260 fs/file_table.c:232
 sock_alloc_file+0xbb/0x260 net/socket.c:398
 sock_map_fd net/socket.c:422 [inline]
 __sys_socket+0x14b/0x2e0 net/socket.c:1517
 __do_sys_socket net/socket.c:1522 [inline]
 __se_sys_socket net/socket.c:1520 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1520
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45da97
Code: 00 00 00 49 89 ca b8 36 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 4a 8b fb ff c3 66 0f 1f 84 00 00 00 00 00 b8 29 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 2d 8b fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd01bd4ba8 EFLAGS: 00000202 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 0000000000000010 RCX: 000000000045da97
RDX: 0000000000000000 RSI: 0000000000080002 RDI: 0000000000000001
RBP: 00000000004c041a R08: 0000000000000000 R09: 0000000000000008
R10: 0000000000000078 R11: 0000000000000202 R12: 0000000000000003
R13: 0000000000000000 R14: 0000000000000006 R15: 00007ffd01bd4ee0