INFO: task syz.9.7049:30015 blocked for more than 145 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.7049      state:D stack:24648 pid:30015 tgid:30014 ppid:26451  task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_timeout+0x9a/0x270
 wait_for_completion+0x2bf/0x5d0
 f2fs_issue_checkpoint+0x376/0x570
 f2fs_do_sync_file+0x869/0x1860
 f2fs_file_write_iter+0x753/0x2410
 vfs_write+0x5c9/0xb30
 ksys_write+0x145/0x250
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f72d598ebe9
RSP: 002b:00007f72d681f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f72d5bc5fa0 RCX: 00007f72d598ebe9
RDX: 0000000000000561 RSI: 0000200000000100 RDI: 0000000000000007
RBP: 00007f72d5a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f72d5bc6038 R14: 00007f72d5bc5fa0 R15: 00007ffef412cba8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
1 lock held by kswapd0/87:
2 locks held by getty/5675:
 #0: ffff8880292170a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
2 locks held by sshd/5830:
 #0: ffff88802344b708 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x19f/0x3d0
 #1: ffffe8ffffc1ff90 (&per_cpu_ptr(pool->acomp_ctx, cpu)->mutex){+.+.}-{4:4}, at: zswap_decompress+0x134/0x810
3 locks held by kworker/u9:22/9375:
 #0: ffff88801b706148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90007ac7bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888121ec80e0 (&type->s_umount_key#54){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0
3 locks held by kworker/0:7/22586:
 #0: ffff88801a480d48 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc900034a7bc0 (free_ipc_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffffffff8e13f978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730
2 locks held by syz.9.7049/30015:
 #0: ffff888028c802f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320
 #1: ffff888121ec8428 (sb_writers#16){.+.+}-{0:0}, at: vfs_write+0x211/0xb30
2 locks held by f2fs_ckpt-7:9/30026:
2 locks held by syz.2.7492/31921:
 #0: ffffffff8f52b9f0 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x304/0x4d0
 #1: ffffffff8e13f978 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730
1 lock held by syz-executor/31935:

=============================================

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 34 Comm: khungtaskd 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
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 nmi_cpu_backtrace+0x39e/0x3d0
 nmi_trigger_cpumask_backtrace+0x17a/0x300
 watchdog+0xf93/0xfe0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31928 Comm: kworker/u9:4 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
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:debug_lockdep_rcu_enabled+0x0/0x40
Code: 76 9b 09 f6 90 0f 0b 90 90 90 eb c4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 31 c0 83 3d 57 dc 29 04 00 74 1e 83 3d 6a 0c 2a 04 00
RSP: 0018:ffffc90003207470 EFLAGS: 00000206
RAX: ffffc90003208000 RBX: ffffffff90408c01 RCX: ffffc900032078f0
RDX: ffffc90003207501 RSI: dffffc0000000000 RDI: ffffc90003207550
RBP: dffffc0000000000 R08: ffffc900032078d8 R09: 0000000000000000
R10: ffffc90003207598 R11: fffff52000640eb5 R12: ffffc900032078e8
R13: ffffc90003200000 R14: ffffc90003207548 R15: ffffffff8172c195
FS:  0000000000000000(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f224b470000 CR3: 0000000107146000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 unwind_next_frame+0x195c/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 kasan_save_track+0x3e/0x80
 __kasan_slab_alloc+0x6c/0x80
 kmem_cache_alloc_node_noprof+0x1bb/0x3c0
 __alloc_skb+0x112/0x2d0
 nsim_dev_trap_report_work+0x29a/0xb80
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
