INFO: task syz-executor:5842 blocked for more than 143 seconds.
      Not tainted 6.15.0-rc2-syzkaller-00493-gac71fabf1567 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D stack:13360 pid:5842  tgid:5842  ppid:1      task_flags:0x400140 flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5382 [inline]
 __schedule+0x1b88/0x5240 kernel/sched/core.c:6767
 __schedule_loop kernel/sched/core.c:6845 [inline]
 schedule+0x163/0x360 kernel/sched/core.c:6860
 __bch2_fs_stop+0x3cd/0x5b0 fs/bcachefs/super.c:651
 generic_shutdown_super+0x13b/0x2d0 fs/super.c:642
 bch2_kill_sb+0x41/0x50 fs/bcachefs/fs.c:2303
 deactivate_locked_super+0xc6/0x130 fs/super.c:473
 cleanup_mnt+0x422/0x4c0 fs/namespace.c:1435
 task_work_run+0x253/0x310 kernel/task_work.c:227
 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:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218
 do_syscall_64+0x100/0x210 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbe9118f497
RSP: 002b:00007ffe7d183d08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fbe91210854 RCX: 00007fbe9118f497
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe7d183dc0
RBP: 00007ffe7d183dc0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffe7d184e50
R13: 00007fbe91210854 R14: 0000000000066f01 R15: 00007ffe7d184e90
 </TASK>

Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
1 lock held by khungtaskd/31:
 #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
 #0: ffffffff8ed3df20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x30/0x180 kernel/locking/lockdep.c:6764
3 locks held by kworker/u8:4/62:
2 locks held by getty/5587:
 #0: ffff8880314240a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc900036e32f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x5bb/0x1700 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/5842:
 #0: ffff88802b1700e0 (&type->s_umount_key#78){+.+.}-{4:4}, at: __super_lock fs/super.c:56 [inline]
 #0: ffff88802b1700e0 (&type->s_umount_key#78){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:71 [inline]
 #0: ffff88802b1700e0 (&type->s_umount_key#78){+.+.}-{4:4}, at: deactivate_super+0xb5/0xf0 fs/super.c:505
2 locks held by syz.0.4320/17887:

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

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.15.0-rc2-syzkaller-00493-gac71fabf1567 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x4ab/0x4e0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x198/0x320 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+0x1058/0x10a0 kernel/hung_task.c:437
 kthread+0x7b9/0x940 kernel/kthread.c:464
 ret_from_fork+0x4d/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: 17887 Comm: syz.0.4320 Not tainted 6.15.0-rc2-syzkaller-00493-gac71fabf1567 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:__lock_release kernel/locking/lockdep.c:5512 [inline]
RIP: 0010:lock_release+0xc9/0x3e0 kernel/locking/lockdep.c:5887
Code: 01 00 00 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 4c 8b 74 24 20 fa 48 c7 c7 f8 56 50 8e e8 0e 47 91 0a 65 ff 05 47 23 ca 11 <c7> 44 24 20 01 00 00 00 83 3d 58 9b c1 0e 00 0f 84 1a 01 00 00 48
RSP: 0018:ffffc9001e0ef558 EFLAGS: 00000002
RAX: 0000000000000000 RBX: ffffffff93686020 RCX: 0000000000080000
RDX: ffffc9000b9d1000 RSI: ffffffff8e5056f8 RDI: ffffffff8ca1b680
RBP: ffffffff84ec542b R08: ffffffff84ec5582 R09: 1ffffffff351ff0c
R10: dffffc0000000000 R11: fffffbfff351ff0d R12: ffffea0001337218
R13: ffff888029b2da00 R14: 0000000000000206 R15: ffffffff8ed3df20
FS:  00007f2716dd26c0(0000) GS:ffff888124f9a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f434c980178 CR3: 000000004ab54000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:871 [inline]
 blk_cgroup_congested+0x1eb/0x200 block/blk-cgroup.c:2263
 __folio_throttle_swaprate+0x84/0x1d0 mm/swapfile.c:3905
 folio_throttle_swaprate include/linux/swap.h:634 [inline]
 shmem_add_to_page_cache+0x7d6/0xcc0 mm/shmem.c:898
 shmem_alloc_and_add_folio+0x958/0x1070 mm/shmem.c:1919
 shmem_get_folio_gfp+0x655/0x1800 mm/shmem.c:2533
 shmem_get_folio mm/shmem.c:2639 [inline]
 shmem_write_begin+0x17e/0x3a0 mm/shmem.c:3289
 generic_perform_write+0x32b/0xa10 mm/filemap.c:4103
 shmem_file_write_iter+0xf9/0x120 mm/shmem.c:3464
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0x711/0xd10 fs/read_write.c:684
 ksys_write+0x19d/0x2d0 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf3/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2715f8cc1f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007f2716dd1df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007f2715f8cc1f
RDX: 0000000001000000 RSI: 00007f270b800000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000006197
R10: 0000200000007482 R11: 0000000000000293 R12: 0000000000000003
R13: 00007f2716dd1ef0 R14: 00007f2716dd1eb0 R15: 00007f270b800000
 </TASK>