loop2: rw=1048577, want=52273, limit=112
attempt to access beyond end of device
loop2: rw=1048577, want=56369, limit=112
attempt to access beyond end of device
loop2: rw=1, want=58385, limit=112
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10501 ticks this GP) idle=1da/1/0x4000000000000002 softirq=92596/92596 fqs=0 
rcu: 	 (t=10502 jiffies g=133125 q=863)
rcu: rcu_preempt kthread starved for 10503 jiffies! g133125 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I25464    10      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2831 [inline]
 __schedule+0x897/0x1e60 kernel/sched/core.c:3472
 schedule+0xfe/0x350 kernel/sched/core.c:3516
 schedule_timeout+0x14a/0x250 kernel/time/timer.c:1803
 rcu_gp_fqs_loop+0x6ba/0x970 kernel/rcu/tree.c:1948
 rcu_gp_kthread+0x2bb/0xc10 kernel/rcu/tree.c:2105
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 0
CPU: 0 PID: 31749 Comm: syz-executor0 Not tainted 5.0.0-rc2+ #27
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:check_kcov_mode kernel/kcov.c:67 [inline]
RIP: 0010:write_comp_data+0x10/0x70 kernel/kcov.c:122
Code: 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 5d c3 0f 1f 00 65 4c 8b 04 25 40 ee 01 00 65 8b 05 10 f6 7f 7e <a9> 00 01 1f 00 75 51 41 8b 80 d8 12 00 00 83 f8 03 75 45 49 8b 80
RSP: 0018:ffff888087ee6d60 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff13
RAX: 0000000080000000 RBX: 0000000000000000 RCX: ffffffff81e25604
RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffff888087ee6d68 R08: ffff88809fb3c3c0 R09: 0000000000000005
R10: 0000000000000000 R11: ffff8880ae62dc7b R12: ffffea00017d0b80
R13: 0000000000000018 R14: 0000000000000001 R15: ffffea00019c9ac8
 PageUptodate include/linux/page-flags.h:472 [inline]
 init_page_buffers+0x1b4/0x570 fs/buffer.c:897
 grow_dev_page fs/buffer.c:954 [inline]
 grow_buffers fs/buffer.c:1016 [inline]
 __getblk_slow fs/buffer.c:1043 [inline]
 __getblk_gfp+0xa80/0xd20 fs/buffer.c:1320
 __bread_gfp+0x2f/0x300 fs/buffer.c:1354
 sb_bread include/linux/buffer_head.h:307 [inline]
 fat_ent_bread+0x16c/0x290 fs/fat/fatent.c:107
 fat_ent_read_block fs/fat/fatent.c:440 [inline]
 fat_alloc_clusters+0x8e6/0x17c0 fs/fat/fatent.c:488
 fat_add_cluster+0x7c/0x170 fs/fat/inode.c:101
 __fat_get_block fs/fat/inode.c:148 [inline]
 fat_get_block+0x361/0xae0 fs/fat/inode.c:183
 __block_write_begin_int+0x605/0x2010 fs/buffer.c:1966
 __block_write_begin fs/buffer.c:2016 [inline]
 block_write_begin+0xd2/0x3a0 fs/buffer.c:2075
 cont_write_begin+0x531/0xa00 fs/buffer.c:2428
 fat_write_begin+0x8d/0x120 fs/fat/inode.c:229
 generic_perform_write+0x2a0/0x6b0 mm/filemap.c:3208
 __generic_file_write_iter+0x25e/0x630 mm/filemap.c:3333
 generic_file_write_iter+0x34e/0x6a0 mm/filemap.c:3361
 call_write_iter include/linux/fs.h:1862 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x764/0xb40 fs/read_write.c:487
 vfs_write+0x20c/0x580 fs/read_write.c:549
 ksys_write+0x105/0x260 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+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:00007f62bf67fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457ec9
RDX: 00000000fffffd97 RSI: 0000000020000180 RDI: 000000000000000a
RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f62bf6806d4
R13: 00000000004c7192 R14: 00000000004dca58 R15: 00000000ffffffff