syzbot

INFO: task syz-executor422:5136 blocked for more than 143 seconds.
      Not tainted 6.9.0-rc7-syzkaller-00183-gcf87f46fd34d #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor422 state:D
 stack:19568 pid:5136  tgid:5136  ppid:5133   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5409 [inline]
 __schedule+0x1796/0x4a00 kernel/sched/core.c:6746
 __schedule_loop kernel/sched/core.c:6823 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6838
 wb_wait_for_completion+0x166/0x290 fs/fs-writeback.c:217
 sync_inodes_sb+0x293/0xb20 fs/fs-writeback.c:2783
 sync_filesystem+0x176/0x230 fs/sync.c:64
 generic_shutdown_super+0x72/0x2d0 fs/super.c:620
 kill_block_super+0x44/0x90 fs/super.c:1675
 xfs_kill_sb+0x15/0x50 fs/xfs/xfs_super.c:2026
 deactivate_locked_super+0xc4/0x130 fs/super.c:472
 cleanup_mnt+0x426/0x4c0 fs/namespace.c:1267
 task_work_run+0x24f/0x310 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x168/0x370 kernel/entry/common.c:218
 do_syscall_64+0x102/0x240 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6ead5c6207
RSP: 002b:00007ffcd0e67318 EFLAGS: 00000206
 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f6ead5c6207
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffcd0e673d0
RBP: 00007ffcd0e673d0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000206 R12: 00007ffcd0e68480
R13: 000055556e248700 R14: 00007ffcd0e684c0 R15: 0000000000000003
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
 #0: ffffffff8e33a138 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #0: ffffffff8e33a138 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x39a/0x820 kernel/rcu/tree_exp.h:939
1 lock held by khungtaskd/29:
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #0: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x2a0 kernel/locking/lockdep.c:6614
2 locks held by getty/4838:
 #0: ffff88802f7e80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002efe2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6b5/0x1e10 drivers/tty/n_tty.c:2201
1 lock held by syz-executor422/5131:
2 locks held by syz-executor422/5132:
 #0: ffff8880523800e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff8880523800e0 (&type->s_umount_key#49){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff8880523800e0 (&type->s_umount_key#49){++++}-{3:3}, at: deactivate_super+0xb5/0xf0 fs/super.c:504
 #1: ffff88801fe927d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:389 [inline]
 #1: ffff88801fe927d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xb20 fs/fs-writeback.c:2781
2 locks held by syz-executor422/5134:
 #0: ffff88802bf240e0 (&type->s_umount_key#49
){++++}-{3:3}
, at: __super_lock fs/super.c:56 [inline]
, at: __super_lock_excl fs/super.c:71 [inline]
, at: deactivate_super+0xb5/0xf0 fs/super.c:504
 #1: 
ffff88801fef87d0
 (
&bdi->wb_switch_rwsem
){+.+.}-{3:3}
, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:389 [inline]
, at: sync_inodes_sb+0x274/0xb20 fs/fs-writeback.c:2781
2 locks held by syz-executor422/5137:
 #0: 
ffff8880219440e0
 (
&type->s_umount_key#49){++++}-{3:3}, at: __super_lock fs/super.c:56 [inline]
&type->s_umount_key#49){++++}-{3:3}, at: __super_lock_excl fs/super.c:71 [inline]
&type->s_umount_key#49){++++}-{3:3}, at: deactivate_super+0xb5/0xf0 fs/super.c:504
 #1: ffff88801ff0c7d0 (&bdi->wb_switch_rwsem
){+.+.}-{3:3}
, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:389 [inline]
, at: sync_inodes_sb+0x274/0xb20 fs/fs-writeback.c:2781
4 locks held by kworker/u8:0/5159:
 #0: 
ffff88801be87148
 (
(wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work kernel/workqueue.c:3242 [inline]
, at: process_scheduled_works+0x8e0/0x17c0 kernel/workqueue.c:3348
 #1: 
ffffc900042afd00
 (
(work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3243 [inline]
){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x17c0 kernel/workqueue.c:3348
 #2: 
ffff888021944610
 (
sb_internal#2){.+.+}-{0:0}, at: xfs_bmapi_convert_delalloc+0x267/0x1330 fs/xfs/libxfs/xfs_bmap.c:4625
 #3: ffff888076f4ed98 (&xfs_nondir_ilock_class#3){++++}-{3:3}, at: xfs_bmapi_convert_delalloc+0x295/0x1330 fs/xfs/libxfs/xfs_bmap.c:4630
7 locks held by kworker/u8:2/5165:
4 locks held by kworker/u8:3/5167:
 #0: ffff88801be87148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3242 [inline]
 #0: ffff88801be87148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x17c0 kernel/workqueue.c:3348
 #1: ffffc9000432fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3243 [inline]
 #1: ffffc9000432fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x17c0 kernel/workqueue.c:3348
 #2: ffff888052380610 (sb_internal#2){.+.+}-{0:0}, at: xfs_bmapi_convert_delalloc+0x267/0x1330 fs/xfs/libxfs/xfs_bmap.c:4625
 #3: ffff888076f4a7d8 (&xfs_nondir_ilock_class#3){++++}-{3:3}, at: xfs_bmapi_convert_delalloc+0x295/0x1330 fs/xfs/libxfs/xfs_bmap.c:4630
2 locks held by kworker/1:7/5308:
3 locks held by syz-executor422/5387:

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

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted 6.9.0-rc7-syzkaller-00183-gcf87f46fd34d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 nmi_cpu_backtrace+0x49c/0x4d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xfde/0x1020 kernel/hung_task.c:380
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8 Comm: kworker/0:1 Not tainted 6.9.0-rc7-syzkaller-00183-gcf87f46fd34d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Workqueue: xfs-buf/loop2 xfs_buf_ioend_work
RIP: 0010:io_serial_in+0x76/0xb0 drivers/tty/serial/8250/8250_port.c:406
Code: 00 72 62 fc 89 e9 41 d3 e6 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 c1 ce c3 fc 44 03 33 44 89 f2 ec <0f> b6 c0 5b 41 5e 41 5f 5d c3 cc cc cc cc 89 e9 80 e1 07 38 c1 7c
RSP: 0018:ffffc900000d7238 EFLAGS: 00000002
RAX: 1ffffffff2944600 RBX: ffffffff94a23760 RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: 0000000000000000 R08: ffffffff85339586 R09: 1ffff11003ece046
R10: dffffc0000000000 R11: ffffffff85339540 R12: dffffc0000000000
R13: 00000000000026d9 R14: 00000000000003fd R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005630b6e3add8 CR3: 0000000024eb8000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:117 [inline]
 serial_lsr_in drivers/tty/serial/8250/8250.h:139 [inline]
 wait_for_lsr drivers/tty/serial/8250/8250_port.c:2071 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3318 [inline]
 serial8250_console_write+0x1099/0x1770 drivers/tty/serial/8250/8250_port.c:3396
 console_emit_next_record kernel/printk/printk.c:2913 [inline]
 console_flush_all+0x865/0xfd0 kernel/printk/printk.c:2979
 console_unlock+0x13b/0x4d0 kernel/printk/printk.c:3048
 vprintk_emit+0x5a6/0x770 kernel/printk/printk.c:2348
 _printk+0xd5/0x120 kernel/printk/printk.c:2373
 print_hex_dump+0x1a6/0x250 lib/hexdump.c:285
 xfs_hex_dump+0x3d/0x50 fs/xfs/xfs_message.c:110
 xfs_buf_verifier_error+0x1ce/0x2a0 fs/xfs/xfs_error.c:460
 xfs_allocbt_read_verify+0x5e/0xd0
 xfs_buf_ioend+0x288/0x730 fs/xfs/xfs_buf.c:1376
 process_one_work kernel/workqueue.c:3267 [inline]
 process_scheduled_works+0xa10/0x17c0 kernel/workqueue.c:3348
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3429
 kthread+0x2f0/0x390 kernel/kthread.c:388
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>