rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P19480/1:b..l
rcu: 	(detected by 0, t=10506 jiffies, g=51717, q=631 ncpus=2)
task:syz.1.1226      state:R  running task     stack:25160 pid:19480 tgid:19478 ppid:16334  task_flags:0x40054c flags:0x00004000
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 preempt_schedule_common+0x83/0xd0
 preempt_schedule+0xae/0xc0
 preempt_schedule_thunk+0x16/0x30
 _raw_spin_unlock+0x3f/0x50
 unmap_page_range+0x3a79/0x4370
 unmap_vmas+0x399/0x580
 exit_mmap+0x248/0xb50
 __mmput+0x118/0x420
 exit_mm+0x1da/0x2c0
 do_exit+0x648/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbb1b58ebe9
RSP: 002b:00007fbb1c3820e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fbb1b7b5fa8 RCX: 00007fbb1b58ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fbb1b7b5fa8
RBP: 00007fbb1b7b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbb1b7b6038 R14: 00007ffe6c0fe0c0 R15: 00007ffe6c0fe1a8
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10505 jiffies! g51717 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=21369
rcu: rcu_preempt kthread starved for 10506 jiffies! g51717 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:I stack:27496 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_timeout+0x12b/0x270
 rcu_gp_fqs_loop+0x301/0x1540
 rcu_gp_kthread+0x99/0x390
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5843 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:rcu_is_watching+0x70/0xb0
Code: c3 98 7f a1 92 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d a9 f2 f9 10 74 11 83 e0 04 c1 e8 02 5b <41> 5e 41 5f e9 87 fd d5 09 cc e8 91 69 8d ff eb e8 48 c7 c7 80 fb
RSP: 0000:ffffc900001e0b60 EFLAGS: 00000002
RAX: 0000000000000001 RBX: 0000000000000802 RCX: 344dc6f5a486d100
RDX: 0000000000000001 RSI: ffffffff8be33660 RDI: ffffffff8be33620
RBP: ffffc900001e0c78 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200003c16c R12: dffffc0000000000
R13: ffffffff84d02752 R14: ffffffff8dbded18 R15: dffffc0000000000
FS:  0000555582a1e500(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d921ff8 CR3: 000000002757a000 CR4: 00000000000006f0
Call Trace:
 <IRQ>
 lock_release+0x4b/0x3e0
 _raw_spin_unlock_irqrestore+0x70/0x110
 debug_object_activate+0x2e2/0x420
 enqueue_hrtimer+0x30/0x3a0
 __hrtimer_run_queues+0x656/0xc60
 hrtimer_interrupt+0x45b/0xaa0
 __sysvec_apic_timer_interrupt+0x10b/0x410
 sysvec_apic_timer_interrupt+0xa1/0xc0
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20
RIP: 0010:lock_acquire+0x18e/0x360
Code: 24 08 00 02 00 00 74 01 fb 65 48 8b 05 4b f4 02 11 48 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e 41 5f 5d <c3> cc cc cc cc cc 65 8b 05 35 34 03 11 85 c0 75 ce 65 8b 05 2a f4
RSP: 0000:ffffc900040b7940 EFLAGS: 00000282
RAX: 344dc6f5a486d100 RBX: ffff88803a514b88 RCX: 344dc6f5a486d100
RDX: 0000000000000000 RSI: ffffffff8be33660 RDI: ffffffff8be33620
RBP: ffffc900040b7c70 R08: 0000000000000001 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10074a2a0f R12: ffff888030a00084
R13: ffff88803a515250 R14: 0000000000000000 R15: 0000000000000000
 _raw_spin_lock+0x2e/0x40
 f2fs_write_checkpoint+0xab0/0x1df0
 kill_f2fs_super+0x2c3/0x6c0
 deactivate_locked_super+0xbc/0x130
 cleanup_mnt+0x425/0x4c0
 task_work_run+0x1d4/0x260
 exit_to_user_mode_loop+0xec/0x110
 do_syscall_64+0x2bd/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0cc718ff17
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe6e631e38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f0cc7211c05 RCX: 00007f0cc718ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe6e631ef0
RBP: 00007ffe6e631ef0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe6e632f80
R13: 00007f0cc7211c05 R14: 000000000002078e R15: 00007ffe6e632fc0
 </TASK>
