INFO: task syz-executor.0:4474 blocked for more than 143 seconds.
      Not tainted 5.15.178-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:20024 pid: 4474 ppid:     1 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 wb_wait_for_completion+0x164/0x290 fs/fs-writeback.c:191
 sync_inodes_sb+0x293/0xab0 fs/fs-writeback.c:2770
 sync_filesystem+0x16b/0x220 fs/sync.c:64
 generic_shutdown_super+0x6b/0x310 fs/super.c:448
 kill_block_super+0x7a/0xe0 fs/super.c:1427
 deactivate_locked_super+0xa0/0x110 fs/super.c:335
 cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
 task_work_run+0x129/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fa35f8a70d7
RSP: 002b:00007fff6bebef68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007fa35f8a70d7
RDX: 0000000000000000 RSI: 000000000000000a RDI: 00007fff6bebf020
RBP: 00007fff6bebf020 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fff6bec00e0
R13: 00007fa35f8f13b9 R14: 0000000000015299 R15: 0000000000000007
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u4:0/9:
 #0: ffff88801b3d9138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90000ce7d20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
1 lock held by khungtaskd/27:
 #0: ffffffff8cb1fce0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3933:
 #0: ffff88802ceab098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900025c62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
2 locks held by syz-executor.0/4474:
 #0: ffff88807d6d60e0 (&type->s_umount_key#32){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
 #1: ffff888020d267d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff888020d267d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3536 Comm: klogd Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0033:0x7fba7845baff
Code: 8b 74 24 40 85 db e9 d7 00 00 00 45 85 c9 79 06 45 89 cf 41 f7 df 48 8d 74 24 68 b9 0a 00 00 00 44 89 f8 31 d2 48 ff ce f7 f1 <83> c2 30 88 16 44 89 fa 41 89 c7 83 fa 09 77 e6 e9 eb 09 00 00 4c
RSP: 002b:00007fff00166b40 EFLAGS: 00000206
RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 000000000000000a
RDX: 0000000000000005 RSI: 00007fff00166ba6 RDI: 000000000000004d
RBP: 0000000000000000 R08: 0000000000000002 R09: 0000000000000035
R10: 0000000000000000 R11: 0000000000000003 R12: 0000000000000003
R13: 00007fff00166db8 R14: 00007fba78553c40 R15: 0000000000000005
FS:  00007fba78327380 GS:  0000000000000000