INFO: task syz-executor:5826 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc4-syzkaller-00021-gca91b9500108 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:17608 pid:5826  tgid:5826  ppid:1      task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x16e2/0x4cd0 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x165/0x360 kernel/sched/core.c:6860
 __bch2_fs_stop+0x3ce/0x5a0 fs/bcachefs/super.c:632
 generic_shutdown_super+0x135/0x2c0 fs/super.c:642
 bch2_kill_sb+0x41/0x50 fs/bcachefs/fs.c:2620
 deactivate_locked_super+0xbc/0x130 fs/super.c:473
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1435
 task_work_run+0x1d4/0x260 kernel/task_work.c:227
 resume_user_mode_work+0x5e/0x80 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x9a/0x120 kernel/entry/common.c:218
 do_syscall_64+0x103/0x210 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc9f178fc97
RSP: 002b:00007ffd9e428f58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fc9f181089d RCX: 00007fc9f178fc97
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd9e429010
RBP: 00007ffd9e429010 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd9e42a0a0
R13: 00007fc9f181089d R14: 000000000005db14 R15: 00007ffd9e42a0e0
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8df3b860 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6764
2 locks held by getty/5580:
 #0: ffff88814cb830a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900030062f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/5826:
 #0: ffff888050f7a0e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff888050f7a0e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff888050f7a0e0 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
1 lock held by syz.1.3360/14850:
 #0: ffff888050f7a0e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff888050f7a0e0 (&type->s_umount_key#53){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:120
1 lock held by syz-executor/15065:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc4-syzkaller-00021-gca91b9500108 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:274 [inline]
 watchdog+0xfee/0x1030 kernel/hung_task.c:437
 kthread+0x711/0x8a0 kernel/kthread.c:464
 ret_from_fork+0x4e/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.15.0-rc4-syzkaller-00021-gca91b9500108 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:81
Code: ee 9d ba f5 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d 03 6b 12 00 f3 0f 1e fa fb f4 <e9> c3 9d ba f5 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffffff8dc07d80 EFLAGS: 00000286
RAX: 313640de1bd16500 RBX: ffffffff81973da8 RCX: 313640de1bd16500
RDX: 0000000000000001 RSI: ffffffff8d748fff RDI: ffffffff8bc1cde0
RBP: ffffffff8dc07ec0 R08: ffff8880b8832b5b R09: 1ffff1101710656b
R10: dffffc0000000000 R11: ffffed101710656c R12: ffffffff8f7ec970
R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1b92a48
FS:  0000000000000000(0000) GS:ffff8881260cc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2dc52e8704 CR3: 000000007c656000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:748
 default_idle_call+0x74/0xb0 kernel/sched/idle.c:117
 cpuidle_idle_call kernel/sched/idle.c:185 [inline]
 do_idle+0x1e8/0x510 kernel/sched/idle.c:325
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:423
 rest_init+0x2de/0x300 init/main.c:743
 start_kernel+0x470/0x4f0 init/main.c:1099
 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:513
 x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:494
 common_startup_64+0x13e/0x147
 </TASK>