Unknown ioctl 21531
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (10500 ticks this GP) idle=3f2/1/0x4000000000000002 softirq=119233/119233 fqs=5250 
rcu: 	 (t=10502 jiffies g=189061 q=1409)
NMI backtrace for cpu 0
CPU: 0 PID: 9765 Comm: syz-executor0 Not tainted 4.20.0+ #3
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+0x1db/0x2d0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree.c:1211
 print_cpu_stall.cold+0x227/0x40c kernel/rcu/tree.c:1348
 check_cpu_stall kernel/rcu/tree.c:1422 [inline]
 rcu_pending kernel/rcu/tree.c:3018 [inline]
 rcu_check_callbacks+0xb32/0x1380 kernel/rcu/tree.c:2521
 update_process_times+0x32/0x80 kernel/time/timer.c:1635
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x3a7/0x1050 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline]
 smp_apic_timer_interrupt+0x18d/0x760 arch/x86/kernel/apic/apic.c:1060
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:page_cache_get_speculative include/linux/pagemap.h:195 [inline]
RIP: 0010:find_get_entry+0x61d/0x10a0 mm/filemap.c:1487
Code: 00 00 48 8b 85 10 fe ff ff 4c 8b 68 08 48 89 d8 48 c1 e8 03 42 80 3c 30 00 0f 85 21 09 00 00 48 c1 eb 03 4d 89 af 40 ff ff ff <31> ff 42 c6 04 33 f8 4c 89 eb 83 e3 01 48 89 de e8 4e ae e1 ff 48
RSP: 0018:ffff888095f870f0 EFLAGS: 00000a02 ORIG_RAX: ffffffffffffff13
RAX: 1ffff11012bf0e4a RBX: 1ffff11012bf0e4a RCX: ffffc90005fd2000
RDX: 0000000000040000 RSI: ffffffff819fd495 RDI: 0000000000000005
RBP: ffff888095f87338 R08: ffff888063c0c300 R09: ffffed1012bf0e31
R10: ffffed1012bf0e30 R11: 0000000000000003 R12: ffffea0000a8c788
R13: ffffea00022f4888 R14: dffffc0000000000 R15: ffff888095f87310
 pagecache_get_page+0xe6/0x1020 mm/filemap.c:1579
 find_or_create_page include/linux/pagemap.h:322 [inline]
 grow_dev_page fs/buffer.c:947 [inline]
 grow_buffers fs/buffer.c:1016 [inline]
 __getblk_slow fs/buffer.c:1043 [inline]
 __getblk_gfp+0x38a/0xd20 fs/buffer.c:1320
 __getblk include/linux/buffer_head.h:380 [inline]
 __breadahead+0x86/0x160 fs/buffer.c:1330
 sb_breadahead include/linux/buffer_head.h:319 [inline]
 fat_dir_readahead fs/fat/dir.c:66 [inline]
 fat__get_entry+0x4b5/0xa40 fs/fat/dir.c:99
 fat_get_entry fs/fat/dir.c:129 [inline]
 fat_search_long+0x345/0x17d0 fs/fat/dir.c:479
 vfat_find+0x10e/0x140 fs/fat/namei_vfat.c:697
 vfat_lookup+0x10a/0x6b0 fs/fat/namei_vfat.c:711
 __lookup_hash+0x122/0x190 fs/namei.c:1546
 filename_create+0x1d6/0x5a0 fs/namei.c:3636
 user_path_create fs/namei.c:3693 [inline]
 do_mknodat+0x1bd/0x530 fs/namei.c:3754
 __do_sys_mknod fs/namei.c:3794 [inline]
 __se_sys_mknod fs/namei.c:3792 [inline]
 __x64_sys_mknod+0x7b/0xb0 fs/namei.c:3792
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457ec9
Code: 6d b7 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 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fa31b71fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000085
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457ec9
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000020000440
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa31b7206d4
R13: 00000000004c39b6 R14: 00000000004d6538 R15: 00000000ffffffff