ODEBUG: object ffffc90003dd7b90 is on stack ffffc90003dd0000, but NOT annotated.
======================================================
WARNING: possible circular locking dependency detected
6.15.0-rc6-next-20250515-syzkaller-g484803582c77 #0 Not tainted
------------------------------------------------------
bch-copygc/loop/6839 is trying to acquire lock:
ffffffff8cd20480 (console_owner){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
ffffffff8cd20480 (console_owner){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:346 [inline]
ffffffff8cd20480 (console_owner){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:288 [inline]
ffffffff8cd20480 (console_owner){....}-{0:0}, at: console_flush_all+0x137/0x9e0 kernel/printk/printk.c:3203

but task is already holding lock:
ffffffff97bedd08 (&obj_hash[i].lock){-.-.}-{2:2}, at: __debug_object_init+0x85/0x3c0 lib/debugobjects.c:741

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&obj_hash[i].lock){-.-.}-{2:2}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
       debug_object_activate+0xbb/0x420 lib/debugobjects.c:818
       debug_work_activate kernel/workqueue.c:664 [inline]
       insert_work+0x30/0x270 kernel/workqueue.c:2180
       __queue_work+0x966/0xc10 kernel/workqueue.c:2341
       queue_work_on+0x176/0x1d0 kernel/workqueue.c:2392
       queue_work include/linux/workqueue.h:662 [inline]
       start_poll_synchronize_rcu_expedited+0xfc/0x140 kernel/rcu/tree_exp.h:1075
       rcu_init+0x108/0x160 kernel/rcu/tree.c:4854
       start_kernel+0x1a9/0x400 init/main.c:991
       x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:311
       x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:292
       common_startup_64+0x13e/0x147

-> #3 (&pool->lock){-.-.}-{2:2}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       __queue_work+0x597/0xc10 kernel/workqueue.c:-1
       queue_work_on+0x176/0x1d0 kernel/workqueue.c:2392
       queue_work include/linux/workqueue.h:662 [inline]
       rpm_suspend+0xb78/0x1190 drivers/base/power/runtime.c:673
       __pm_runtime_idle+0xad/0x110 drivers/base/power/runtime.c:1112
       pm_runtime_put include/linux/pm_runtime.h:470 [inline]
       __device_attach+0x258/0x370 drivers/base/dd.c:1047
       bus_probe_device+0x12d/0x200 drivers/base/bus.c:537
       device_add+0x4ee/0x9b0 drivers/base/core.c:3692
       serial_base_port_add+0x25a/0x3a0 drivers/tty/serial/serial_base_bus.c:179
       serial_core_port_device_add drivers/tty/serial/serial_core.c:3341 [inline]
       serial_core_register_port+0x35c/0x24a0 drivers/tty/serial/serial_core.c:3380
       serial8250_register_8250_port+0x12ab/0x1b90 drivers/tty/serial/8250/8250_core.c:822
       serial_pnp_probe+0x3d7/0x5e0 drivers/tty/serial/8250/8250_pnp.c:480
       pnp_device_probe+0x25a/0x3d0 drivers/pnp/driver.c:111
       call_driver_probe drivers/base/dd.c:-1 [inline]
       really_probe+0x241/0x860 drivers/base/dd.c:657
       __driver_probe_device+0x138/0x280 drivers/base/dd.c:799
       driver_probe_device+0x4a/0x3a0 drivers/base/dd.c:829
       __driver_attach+0x26d/0x5b0 drivers/base/dd.c:1215
       bus_for_each_dev+0x20e/0x270 drivers/base/bus.c:370
       bus_add_driver+0x2f1/0x570 drivers/base/bus.c:678
       driver_register+0x16e/0x2b0 drivers/base/driver.c:249
       serial8250_init+0x8f/0x160 drivers/tty/serial/8250/8250_platform.c:315
       do_one_initcall+0x1ad/0x5b0 init/main.c:1273
       do_initcall_level+0x104/0x190 init/main.c:1335
       do_initcalls+0x59/0xa0 init/main.c:1351
       kernel_init_freeable+0x334/0x4a0 init/main.c:1583
       kernel_init+0x17/0x130 init/main.c:1473
       ret_from_fork+0x2bd/0x570 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

-> #2 (&dev->power.lock){-.-.}-{3:3}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
       __pm_runtime_resume+0xa5/0x110 drivers/base/power/runtime.c:1179
       pm_runtime_get include/linux/pm_runtime.h:418 [inline]
       __uart_start+0x122/0x350 drivers/tty/serial/serial_core.c:149
       uart_write+0xc8/0x110 drivers/tty/serial/serial_core.c:636
       process_output_block drivers/tty/n_tty.c:561 [inline]
       n_tty_write+0xe36/0x1230 drivers/tty/n_tty.c:2377
       iterate_tty_write drivers/tty/tty_io.c:1006 [inline]
       file_tty_write+0x497/0x840 drivers/tty/tty_io.c:1081
       new_sync_write fs/read_write.c:591 [inline]
       vfs_write+0x724/0x930 fs/read_write.c:684
       ksys_write+0x108/0x1f0 fs/read_write.c:736
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&port_lock_key){-.-.}-{3:3}:
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
       uart_port_lock_irqsave include/linux/serial_core.h:717 [inline]
       serial8250_console_write+0x147/0x15b0 drivers/tty/serial/8250/8250_port.c:3415
       console_emit_next_record kernel/printk/printk.c:3138 [inline]
       console_flush_all+0x55b/0x9e0 kernel/printk/printk.c:3226
       __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
       console_unlock+0xb7/0x1e0 kernel/printk/printk.c:3325
       vprintk_emit+0x3ea/0x5f0 kernel/printk/printk.c:2450
       _printk+0xce/0x120 kernel/printk/printk.c:2475
       register_console+0x7bb/0xe40 kernel/printk/printk.c:4125
       univ8250_console_init+0x3a/0x70 drivers/tty/serial/8250/8250_core.c:513
       console_init+0x10e/0x430 kernel/printk/printk.c:4323
       start_kernel+0x252/0x400 init/main.c:1035
       x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:311
       x86_64_start_kernel+0x66/0x70 arch/x86/kernel/head64.c:292
       common_startup_64+0x13e/0x147

-> #0 (console_owner){....}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3168 [inline]
       check_prevs_add kernel/locking/lockdep.c:3287 [inline]
       validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
       __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
       lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
       console_lock_spinning_enable kernel/printk/printk.c:1924 [inline]
       console_emit_next_record kernel/printk/printk.c:3132 [inline]
       console_flush_all+0x4fc/0x9e0 kernel/printk/printk.c:3226
       __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
       console_unlock+0xb7/0x1e0 kernel/printk/printk.c:3325
       vprintk_emit+0x3ea/0x5f0 kernel/printk/printk.c:2450
       _printk+0xce/0x120 kernel/printk/printk.c:2475
       debug_object_is_on_stack lib/debugobjects.c:-1 [inline]
       lookup_object_or_alloc lib/debugobjects.c:688 [inline]
       __debug_object_init+0x2c8/0x3c0 lib/debugobjects.c:743
       rhashtable_init_noprof+0x6c5/0xa70 lib/rhashtable.c:1085
       bch2_copygc_thread+0x106/0xb90 fs/bcachefs/movinggc.c:354
       kthread+0x600/0x770 kernel/kthread.c:464
       ret_from_fork+0x2bd/0x570 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

other info that might help us debug this:

Chain exists of:
  console_owner --> &pool->lock --> &obj_hash[i].lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&obj_hash[i].lock);
                               lock(&pool->lock);
                               lock(&obj_hash[i].lock);
  lock(console_owner);

 *** DEADLOCK ***

3 locks held by bch-copygc/loop/6839:
 #0: ffffffff97bedd08 (&obj_hash[i].lock){-.-.}-{2:2}, at: __debug_object_init+0x85/0x3c0 lib/debugobjects.c:741
 #1: ffffffff8cd204e0 (console_lock){+.+.}-{0:0}, at: _printk+0xce/0x120 kernel/printk/printk.c:2475
 #2: ffffffff8cc07db0 (console_srcu){....}-{0:0}, at: rcu_try_lock_acquire include/linux/rcupdate.h:336 [inline]
 #2: ffffffff8cc07db0 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:346 [inline]
 #2: ffffffff8cc07db0 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:288 [inline]
 #2: ffffffff8cc07db0 (console_srcu){....}-{0:0}, at: console_flush_all+0x137/0x9e0 kernel/printk/printk.c:3203

stack backtrace:
CPU: 1 UID: 0 PID: 6839 Comm: bch-copygc/loop Not tainted 6.15.0-rc6-next-20250515-syzkaller-g484803582c77 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xfc/0x190 lib/dump_stack.c:120
 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2046
 check_noncircular+0x134/0x160 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3168 [inline]
 check_prevs_add kernel/locking/lockdep.c:3287 [inline]
 validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3911
 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
 console_lock_spinning_enable kernel/printk/printk.c:1924 [inline]
 console_emit_next_record kernel/printk/printk.c:3132 [inline]
 console_flush_all+0x4fc/0x9e0 kernel/printk/printk.c:3226
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0xb7/0x1e0 kernel/printk/printk.c:3325
 vprintk_emit+0x3ea/0x5f0 kernel/printk/printk.c:2450
 _printk+0xce/0x120 kernel/printk/printk.c:2475
 debug_object_is_on_stack lib/debugobjects.c:-1 [inline]
 lookup_object_or_alloc lib/debugobjects.c:688 [inline]
 __debug_object_init+0x2c8/0x3c0 lib/debugobjects.c:743
 rhashtable_init_noprof+0x6c5/0xa70 lib/rhashtable.c:1085
 bch2_copygc_thread+0x106/0xb90 fs/bcachefs/movinggc.c:354
 kthread+0x600/0x770 kernel/kthread.c:464
 ret_from_fork+0x2bd/0x570 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
------------[ cut here ]------------
WARNING: CPU: 1 PID: 6839 at lib/debugobjects.c:655 debug_object_is_on_stack lib/debugobjects.c:655 [inline]
WARNING: CPU: 1 PID: 6839 at lib/debugobjects.c:655 lookup_object_or_alloc lib/debugobjects.c:688 [inline]
WARNING: CPU: 1 PID: 6839 at lib/debugobjects.c:655 __debug_object_init+0x2c9/0x3c0 lib/debugobjects.c:743
Modules linked in:
CPU: 1 UID: 0 PID: 6839 Comm: bch-copygc/loop Not tainted 6.15.0-rc6-next-20250515-syzkaller-g484803582c77 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:debug_object_is_on_stack lib/debugobjects.c:655 [inline]
RIP: 0010:lookup_object_or_alloc lib/debugobjects.c:688 [inline]
RIP: 0010:__debug_object_init+0x2c9/0x3c0 lib/debugobjects.c:743
Code: eb 05 cc 41 ff c7 44 89 3d 54 c1 79 13 48 c7 c1 c0 91 a2 8a 48 c7 c7 20 92 a2 8a 84 c0 48 0f 45 f9 48 89 de e8 b8 b5 da fc 90 <0f> 0b 90 e9 c0 fe ff ff e8 3a 1c 00 00 8b 05 ac 27 f8 08 3b 05 aa
RSP: 0018:ffffc90003dd76d8 EFLAGS: 00010046
RAX: 0000000000000050 RBX: ffffc90003dd7b90 RCX: 17201c1b3b630b00
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 00000000ffffffff
RBP: ffff88802d5c8020 R08: ffff8880b8b24293 R09: 1ffff11017164852
R10: dffffc0000000000 R11: ffffed1017164853 R12: ffff88805d8f1278
R13: ffff888078df5850 R14: dffffc0000000000 R15: 0000000000000001
FS:  0000000000000000(0000) GS:ffff888128293000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7bfa7ed000 CR3: 000000002714c000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rhashtable_init_noprof+0x6c5/0xa70 lib/rhashtable.c:1085
 bch2_copygc_thread+0x106/0xb90 fs/bcachefs/movinggc.c:354
 kthread+0x600/0x770 kernel/kthread.c:464
 ret_from_fork+0x2bd/0x570 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>