INFO: task syz.2.54:6236 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.54        state:D stack:17448 pid:6236  tgid:6235  ppid:5861   task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 __closure_sync+0x163/0x220
 bch2_read_iter+0x1034/0x1440
 vfs_read+0x55a/0xa30
 ksys_read+0x145/0x250
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5d3c58ebe9
RSP: 002b:00007f5d3d4d1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 00007f5d3c7b5fa0 RCX: 00007f5d3c58ebe9
RDX: 0000000000001000 RSI: 0000200000001400 RDI: 0000000000000004
RBP: 00007f5d3c611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5d3c7b6038 R14: 00007f5d3c7b5fa0 R15: 00007ffea01eadf8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/35:
 #0: ffffffff8e139ee0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
2 locks held by getty/5681:
 #0: ffff88802913a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70
 #1: ffffc900029032f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400
1 lock held by syz.2.54/6236:
 #0: ffff8880223252f8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x247/0x320
1 lock held by syz.4.400/9370:
1 lock held by syz.6.401/9382:

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 35 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: 9382 Comm: syz.6.401 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:preempt_count_add+0x3b/0x1a0
Code: ff df 48 c7 c0 20 a3 ab 99 48 c1 e8 03 42 0f b6 04 38 84 c0 0f 85 f1 00 00 00 83 3d 2e a7 1b 18 00 75 07 65 8b 05 35 54 10 11 <65> 01 3d 2e 54 10 11 48 c7 c0 20 a3 ab 99 48 c1 e8 03 42 0f b6 04
RSP: 0000:ffffc90003bf7d58 EFLAGS: 00000246
RAX: 0000000080000000 RBX: 0000000000000001 RCX: ffffffff99aba303
RDX: 0000000000000001 RSI: 0000000000000017 RDI: 0000000000000001
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff820a60e1
R10: dffffc0000000000 R11: ffffed10217db3e1 R12: 0000000000001254
R13: ffff88810a51d640 R14: ffff88811b181a00 R15: dffffc0000000000
FS:  00007f80661186c0(0000) GS:ffff8881a3c1b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f805b80e000 CR3: 0000000119642000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 count_memcg_events+0x69/0x270
 count_memcg_event_mm+0x14c/0x260
 handle_mm_fault+0x50f/0x8e0
 do_user_addr_fault+0xa81/0x1390
 exc_page_fault+0x76/0xf0
 asm_exc_page_fault+0x26/0x30
RIP: 0033:0x7f8065250c46
Code: f0 72 6e 48 63 cd 48 01 c1 49 39 4f 08 72 4c 8d 4d ff 85 ed 74 33 66 0f 1f 44 00 00 48 39 f0 72 1b 4d 8b 07 49 89 c1 49 29 f1 <47> 0f b6 0c 08 45 84 c9 74 08 45 88 0c 00 49 8b 47 10 48 83 c0 01
RSP: 002b:00007f80661174a0 EFLAGS: 00010206
RAX: 000000000080e001 RBX: 00007f8066117540 RCX: 000000000000007c
RDX: 0000000000000001 RSI: 0000000000000001 RDI: 00007f80661175e0
RBP: 0000000000000102 R08: 00007f805b000000 R09: 000000000080e000
R10: 0000000000000000 R11: 00007f8066117550 R12: 0000000000000001
R13: 00007f806542da20 R14: 0000000000000000 R15: 00007f80661175e0
 </TASK>
