rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (1 GPs behind) idle=e3e/1/0x4000000000000002 softirq=20764/20765 fqs=5191 
rcu: 	 (t=10500 jiffies g=24825 q=1439)
NMI backtrace for cpu 1
CPU: 1 PID: 10889 Comm: syz-executor0 Not tainted 4.20.0-rc2+ #119
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+0x244/0x39d lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1e8/0x22a 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+0x16f/0x1bc kernel/rcu/tree.c:1195
 print_cpu_stall.cold.67+0x1f3/0x3c7 kernel/rcu/tree.c:1334
 check_cpu_stall kernel/rcu/tree.c:1408 [inline]
 rcu_pending kernel/rcu/tree.c:2961 [inline]
 rcu_check_callbacks+0xf3b/0x13f0 kernel/rcu/tree.c:2506
 update_process_times+0x2d/0x70 kernel/time/timer.c:1636
 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164
 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274
 __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
 __hrtimer_run_queues+0x41c/0x10d0 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x313/0x780 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1034 [inline]
 smp_apic_timer_interrupt+0x1a1/0x760 arch/x86/kernel/apic/apic.c:1059
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:804
 </IRQ>
RIP: 0010:__sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:94
Code: dd 28 00 00 00 4d 39 d0 72 1b 49 83 c1 01 4a 89 7c 10 e0 4a 89 74 10 e8 4a 89 54 10 f0 4a 89 4c d8 20 4c 89 08 5d c3 66 90 55 <48> 89 e5 48 8b 75 08 65 48 8b 04 25 40 ee 01 00 65 8b 15 c8 62 82
RSP: 0018:ffff88817db66230 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 0000000000040000 RBX: 1ffff1102fb6cc53 RCX: ffffc90005e5a000
RDX: 0000000000040000 RSI: ffffffff8860cf60 RDI: ffffffff8860cfa0
RBP: ffff88817db66270 R08: ffffed103b5e5b68 R09: ffffed103b5e5b67
R10: ffffed103b5e5b67 R11: ffff8881daf2db3b R12: 0000000000000001
R13: ffffffff8860cfa0 R14: ffffffff8860cf60 R15: ffff88817db66400
 debug_smp_processor_id+0x1c/0x20 lib/smp_processor_id.c:56
 rcu_lockdep_current_cpu_online+0xc9/0x210 kernel/rcu/tree.c:954
 rcu_read_lock_held+0x90/0xc0 kernel/rcu/update.c:279
 xa_entry include/linux/xarray.h:709 [inline]
 xas_descend+0x413/0x510 lib/xarray.c:198
 xas_load+0x145/0x1e0 lib/xarray.c:234
 find_get_entry+0x3ca/0x1120 mm/filemap.c:1415
 pagecache_get_page+0x12f/0xf00 mm/filemap.c:1518
 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+0x3aa/0xd50 fs/buffer.c:1320
 __bread_gfp+0x2d/0x310 fs/buffer.c:1354
 sb_bread include/linux/buffer_head.h:307 [inline]
 fat_ent_bread+0x173/0x290 fs/fat/fatent.c:107
 fat_ent_read_block fs/fat/fatent.c:442 [inline]
 fat_alloc_clusters+0x8db/0x16f0 fs/fat/fatent.c:490
 fat_add_cluster+0x84/0x160 fs/fat/inode.c:101
 __fat_get_block fs/fat/inode.c:148 [inline]
 fat_get_block+0x385/0xb30 fs/fat/inode.c:183
 __block_write_begin_int+0x5ef/0x1d90 fs/buffer.c:1966
 __block_write_begin fs/buffer.c:2016 [inline]
 block_write_begin+0xda/0x370 fs/buffer.c:2075
 cont_write_begin+0x5ba/0x920 fs/buffer.c:2428
 fat_write_begin+0x8d/0x120 fs/fat/inode.c:229
 generic_perform_write+0x3aa/0x6a0 mm/filemap.c:3140
 __generic_file_write_iter+0x26e/0x630 mm/filemap.c:3265
 generic_file_write_iter+0x34d/0x6b0 mm/filemap.c:3293
 call_write_iter include/linux/fs.h:1857 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x6b8/0x9f0 fs/read_write.c:487
 vfs_write+0x1fc/0x560 fs/read_write.c:549
 ksys_write+0x101/0x260 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: fd b3 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 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f93fb705c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569
RDX: 00000000fffffd97 RSI: 0000000020000180 RDI: 0000000000000007
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f93fb7066d4
R13: 00000000004c5893 R14: 00000000004d95a0 R15: 00000000ffffffff