syzbot

Buffer I/O error on dev loop0, logical block 8176, async page read
INFO: rcu_preempt self-detected stall on CPU
	0-...: (1 GPs behind) idle=25b/140000000000001/0 softirq=12446/12448 fqs=6247 
	 (t=12500 jiffies g=2836 c=2835 q=56)
Task dump for CPU 0:
syz-executor1   R  running task    28856  8927   3849 0x0000000c
 ffff8801db207c18 ffffffff814225a9 ffff8801db221b80 0000000000000000
 dffffc0000000000 ffffffff844e0300 ffffffff844e0304 ffff8801db207c38
 ffffffff814228cd ffffffff844e0280 0000000000000000 ffff8801db207ca0
Call Trace:
 <IRQ> [  281.306841]  [<ffffffff814225a9>] sched_show_task.cold.127+0x1c9/0x279 kernel/sched/core.c:5321
 [<ffffffff814228cd>] dump_cpu_task+0x79/0x7e kernel/sched/core.c:9046
 [<ffffffff8142ca6e>] rcu_dump_cpu_stacks+0x191/0x1c1 kernel/rcu/tree.c:1303
 [<ffffffff8142d6aa>] print_cpu_stall kernel/rcu/tree.c:1446 [inline]
 [<ffffffff8142d6aa>] check_cpu_stall kernel/rcu/tree.c:1514 [inline]
 [<ffffffff8142d6aa>] __rcu_pending kernel/rcu/tree.c:3487 [inline]
 [<ffffffff8142d6aa>] rcu_pending kernel/rcu/tree.c:3551 [inline]
 [<ffffffff8142d6aa>] rcu_check_callbacks.cold.79+0x43a/0xd27 kernel/rcu/tree.c:2880
 [<ffffffff8129ea40>] update_process_times+0x30/0x70 kernel/time/timer.c:1629
 [<ffffffff812ca615>] tick_sched_handle.isra.14+0x55/0xf0 kernel/time/tick-sched.c:151
 [<ffffffff812cae32>] tick_sched_timer+0x72/0x120 kernel/time/tick-sched.c:1190
 [<ffffffff812a26f5>] __run_hrtimer kernel/time/hrtimer.c:1255 [inline]
 [<ffffffff812a26f5>] __hrtimer_run_queues+0x375/0xe50 kernel/time/hrtimer.c:1319
 [<ffffffff812a3c31>] hrtimer_interrupt+0x1b1/0x430 kernel/time/hrtimer.c:1353
 [<ffffffff810b0554>] local_apic_timer_interrupt+0x74/0xa0 arch/x86/kernel/apic/apic.c:935
 [<ffffffff838d6adc>] smp_apic_timer_interrupt+0x7c/0xa0 arch/x86/kernel/apic/apic.c:959
 [<ffffffff838d2c70>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> [  281.416671]  [<ffffffff8160d178>] ? do_make_slave fs/pnode.c:84 [inline]
 <EOI> [  281.416671]  [<ffffffff8160d178>] ? change_mnt_propagation+0x88/0xbd0 fs/pnode.c:130
 [<ffffffff815d9526>] umount_tree+0x326/0x820 fs/namespace.c:1515
 [<ffffffff815e1730>] attach_recursive_mnt+0x750/0x8f0 fs/namespace.c:2057
 [<ffffffff815e1a3f>] graft_tree+0x16f/0x1f0 fs/namespace.c:2121
 [<ffffffff815e43ff>] do_loopback fs/namespace.c:2242 [inline]
 [<ffffffff815e43ff>] do_mount+0x1f5f/0x2740 fs/namespace.c:2828
 [<ffffffff815e55be>] SYSC_mount fs/namespace.c:3050 [inline]
 [<ffffffff815e55be>] SyS_mount+0xfe/0x110 fs/namespace.c:3027
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff838d1313>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb