INFO: task syz.6.1880:18556 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.1880      state:D stack:28616 pid:18556 tgid:18530 ppid:16296  task_flags:0x400040 flags:0x00004006
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_write_slowpath+0x872/0xfe0
 down_write+0x1ab/0x1f0
 path_openat+0x8da/0x3830
 do_filp_open+0x1fa/0x410
 do_sys_openat2+0x121/0x1c0
 __x64_sys_open+0x11e/0x150
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5f1c98ebe9
RSP: 002b:00007f5f1d71f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f5f1cbc6180 RCX: 00007f5f1c98ebe9
RDX: 0000000000000086 RSI: 0000000000064842 RDI: 0000200000000ec0
RBP: 00007f5f1ca11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5f1cbc6218 R14: 00007f5f1cbc6180 R15: 00007ffd6b03d7a8
 </TASK>
INFO: task syz.6.1880:18557 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.1880      state:D stack:28936 pid:18557 tgid:18530 ppid:16296  task_flags:0x400040 flags:0x00004004
Call Trace:
 <TASK>
 __schedule+0x1798/0x4cc0
 schedule+0x165/0x360
 schedule_preempt_disabled+0x13/0x30
 rwsem_down_read_slowpath+0x5fd/0x8f0
 down_read+0x98/0x2e0
 path_openat+0x8cb/0x3830
 do_filp_open+0x1fa/0x410
 do_sys_openat2+0x121/0x1c0
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5f1c98ebe9
RSP: 002b:00007f5f1a7f4038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f5f1cbc6270 RCX: 00007f5f1c98ebe9
RDX: 0000000000101101 RSI: 0000200000000300 RDI: ffffffffffffff9c
RBP: 00007f5f1ca11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000013b R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5f1cbc6308 R14: 00007f5f1cbc6270 R15: 00007ffd6b03d7a8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/34:
 #0: ffffffff8e139f20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180
4 locks held by kworker/u9:4/2997:
 #0: ffff8881001ee148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0
 #1: ffffc90009947bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0
 #2: ffff888106ce40e0 (&type->s_umount_key#55){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0
 #3: ffff88802a402fe0 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530
2 locks held by getty/5670:
 #0: ffff88810e7450a0 (&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
4 locks held by syz.6.1880/18531:
2 locks held by syz.6.1880/18556:
 #0: ffff888106ce4428 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90
 #1: ffff88802a403390 (&type->i_mutex_dir_key#9){++++}-{4:4}, at: path_openat+0x8da/0x3830
2 locks held by syz.6.1880/18557:
 #0: ffff888106ce4428 (sb_writers#13){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90
 #1: ffff88802a403390 (&type->i_mutex_dir_key#9){++++}-{4:4}, at: path_openat+0x8cb/0x3830
1 lock held by syz-executor/18722:
 #0: ffffffff8e88e5c8 (bio_slab_lock){+.+.}-{4:4}, at: bioset_exit+0x44a/0x690
2 locks held by syz-executor/19776:
 #0: ffffffff8e88e5c8 (bio_slab_lock){+.+.}-{4:4}, at: bioset_exit+0x44a/0x690
 #1: ffffffff8e13f880 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x570
2 locks held by syz.5.2222/20884:

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

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: 19776 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:check_preemption_disabled+0x63/0x120
Code: 08 0f 85 cc 00 00 00 48 83 c4 10 5b 41 5e 41 5f 5d e9 81 c9 02 00 cc 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 <74> c8 65 4c 8b 3c 25 08 80 a0 92 41 f6 47 2f 04 74 0a 41 83 bf 18
RSP: 0018:ffffc9000649f760 EFLAGS: 00000046
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000080000000
RDX: 0000000000000000 RSI: ffffffff8d9cbe56 RDI: ffffffff8be33880
RBP: ffffffff8172c195 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc9000649f958 R11: ffffffff81ac3aa0 R12: 0000000000000002
R13: ffffffff8e139f20 R14: 0000000000000000 R15: 0000000000000246
FS:  000055557bd00500(0000) GS:ffff8881a3c18000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f04595bd000 CR3: 000000002252a000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 lock_acquire+0xe7/0x360
 unwind_next_frame+0xc2/0x2390
 arch_stack_walk+0x11c/0x150
 stack_trace_save+0x9c/0xe0
 save_stack+0xf5/0x1f0
 __reset_page_owner+0x71/0x1f0
 __free_frozen_pages+0xbc4/0xd30
 vfree+0x25a/0x400
 bch2_fs_btree_write_buffer_exit+0x179/0x1e0
 bch2_fs_release+0x297/0x830
 kobject_put+0x22b/0x480
 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: 0033:0x7f83f578ff17
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:00007ffc8dd8ebd8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f83f5811c05 RCX: 00007f83f578ff17
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc8dd8ec90
RBP: 00007ffc8dd8ec90 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffc8dd8fd20
R13: 00007f83f5811c05 R14: 00000000000d5ae6 R15: 00007ffc8dd8fd60
 </TASK>
