ODEBUG: object ffffc9000b9dfa98 is on stack ffffc9000b9d8000, but NOT annotated.
======================================================
WARNING: possible circular locking dependency detected
6.15.0-syzkaller-12426-ge271ed52b344 #0 Not tainted
------------------------------------------------------
bch-copygc/loop/17570 is trying to acquire lock:
ffffffff8e4d2240 (console_owner){-.-.}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:2048 [inline]
ffffffff8e4d2240 (console_owner){-.-.}-{0:0}, at: vprintk_emit+0x4d4/0x6d0 kernel/printk/printk.c:2449

but task is already holding lock:
ffffffff9b04a6a8 (&obj_hash[i].lock){-.-.}-{2:2}, at: __debug_object_init+0xec/0x3d0 lib/debugobjects.c:741

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&obj_hash[i].lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
       debug_object_activate+0x14c/0x4c0 lib/debugobjects.c:818
       debug_work_activate kernel/workqueue.c:664 [inline]
       insert_work+0x2e/0x230 kernel/workqueue.c:2180
       __queue_work+0x97e/0x10f0 kernel/workqueue.c:2341
       queue_work_on+0x15f/0x1f0 kernel/workqueue.c:2392
       queue_work include/linux/workqueue.h:662 [inline]
       start_poll_synchronize_rcu_expedited+0x113/0x190 kernel/rcu/tree_exp.h:1075
       rcu_init+0xe95/0x1630 kernel/rcu/tree.c:4854
       start_kernel+0x1df/0x4d0 init/main.c:991
       x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307
       x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288
       common_startup_64+0x13e/0x148

-> #2 (&pool->lock){-.-.}-{2:2}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       __queue_work+0x26b/0x10f0 kernel/workqueue.c:2301
       queue_work_on+0x15f/0x1f0 kernel/workqueue.c:2392
       serial8250_rx_chars drivers/tty/serial/8250/8250_port.c:1787 [inline]
       serial8250_handle_irq+0x6c4/0xcb0 drivers/tty/serial/8250/8250_port.c:1945
       serial8250_default_handle_irq+0x9a/0x210 drivers/tty/serial/8250/8250_port.c:1970
       serial8250_interrupt+0x106/0x210 drivers/tty/serial/8250/8250_core.c:86
       __handle_irq_event_percpu+0x22c/0x7d0 kernel/irq/handle.c:158
       handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
       handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210
       handle_edge_irq+0x28e/0xab0 kernel/irq/chip.c:789
       generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
       handle_irq arch/x86/kernel/irq.c:254 [inline]
       call_irq_handler arch/x86/kernel/irq.c:266 [inline]
       __common_interrupt+0xe2/0x250 arch/x86/kernel/irq.c:292
       common_interrupt+0xba/0xe0 arch/x86/kernel/irq.c:285
       asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
       __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
       _raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:194
       __unix_dgram_recvmsg+0x313/0xc50 net/unix/af_unix.c:2529
       unix_dgram_recvmsg+0xd0/0x110 net/unix/af_unix.c:2604
       sock_recvmsg_nosec net/socket.c:1017 [inline]
       ____sys_recvmsg+0x5f9/0x6b0 net/socket.c:2784
       ___sys_recvmsg+0x114/0x1a0 net/socket.c:2828
       do_recvmmsg+0x2fe/0x750 net/socket.c:2923
       __sys_recvmmsg net/socket.c:2997 [inline]
       __do_sys_recvmmsg net/socket.c:3020 [inline]
       __se_sys_recvmmsg net/socket.c:3013 [inline]
       __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3013
       do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
       do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&port_lock_key){-.-.}-{3:3}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
       uart_port_lock_irqsave include/linux/serial_core.h:715 [inline]
       serial8250_console_write+0x181/0x1890 drivers/tty/serial/8250/8250_port.c:3415
       console_emit_next_record kernel/printk/printk.c:3138 [inline]
       console_flush_all+0x801/0xc60 kernel/printk/printk.c:3226
       __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
       console_unlock+0xd8/0x210 kernel/printk/printk.c:3325
       vprintk_emit+0x418/0x6d0 kernel/printk/printk.c:2450
       _printk+0xc7/0x100 kernel/printk/printk.c:2475
       register_console+0xc2d/0x11b0 kernel/printk/printk.c:4125
       univ8250_console_init+0x5f/0x90 drivers/tty/serial/8250/8250_core.c:513
       console_init+0x14f/0x680 kernel/printk/printk.c:4323
       start_kernel+0x29f/0x4d0 init/main.c:1035
       x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:307
       x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:288
       common_startup_64+0x13e/0x148

-> #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 kernel/locking/lockdep.c:3911 [inline]
       __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
       lock_acquire kernel/locking/lockdep.c:5871 [inline]
       lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
       console_trylock_spinning kernel/printk/printk.c:2048 [inline]
       vprintk_emit+0x4e5/0x6d0 kernel/printk/printk.c:2449
       _printk+0xc7/0x100 kernel/printk/printk.c:2475
       debug_object_is_on_stack lib/debugobjects.c:649 [inline]
       lookup_object_or_alloc.part.0+0x3d7/0x590 lib/debugobjects.c:688
       lookup_object_or_alloc lib/debugobjects.c:665 [inline]
       __debug_object_init+0x2a9/0x3d0 lib/debugobjects.c:743
       __init_work+0x4c/0x60 kernel/workqueue.c:677
       rhashtable_init_noprof+0x49f/0x7e0 lib/rhashtable.c:1085
       bch2_copygc_thread+0xf6/0xdd0 fs/bcachefs/movinggc.c:353
       kthread+0x3c5/0x780 kernel/kthread.c:464
       ret_from_fork+0x5d7/0x6f0 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 ***

1 lock held by bch-copygc/loop/17570:
 #0: ffffffff9b04a6a8 (&obj_hash[i].lock){-.-.}-{2:2}, at: __debug_object_init+0xec/0x3d0 lib/debugobjects.c:741

stack backtrace:
CPU: 0 UID: 0 PID: 17570 Comm: bch-copygc/loop Not tainted 6.15.0-syzkaller-12426-ge271ed52b344 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2046
 check_noncircular+0x14c/0x170 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 kernel/locking/lockdep.c:3911 [inline]
 __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240
 lock_acquire kernel/locking/lockdep.c:5871 [inline]
 lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828
 console_trylock_spinning kernel/printk/printk.c:2048 [inline]
 vprintk_emit+0x4e5/0x6d0 kernel/printk/printk.c:2449
 _printk+0xc7/0x100 kernel/printk/printk.c:2475
 debug_object_is_on_stack lib/debugobjects.c:649 [inline]
 lookup_object_or_alloc.part.0+0x3d7/0x590 lib/debugobjects.c:688
 lookup_object_or_alloc lib/debugobjects.c:665 [inline]
 __debug_object_init+0x2a9/0x3d0 lib/debugobjects.c:743
 __init_work+0x4c/0x60 kernel/workqueue.c:677
 rhashtable_init_noprof+0x49f/0x7e0 lib/rhashtable.c:1085
 bch2_copygc_thread+0xf6/0xdd0 fs/bcachefs/movinggc.c:353
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
------------[ cut here ]------------
WARNING: CPU: 0 PID: 17570 at lib/debugobjects.c:655 debug_object_is_on_stack lib/debugobjects.c:655 [inline]
WARNING: CPU: 0 PID: 17570 at lib/debugobjects.c:655 lookup_object_or_alloc.part.0+0x2b1/0x590 lib/debugobjects.c:688
Modules linked in:
CPU: 0 UID: 0 PID: 17570 Comm: bch-copygc/loop Not tainted 6.15.0-syzkaller-12426-ge271ed52b344 #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.part.0+0x2b1/0x590 lib/debugobjects.c:688
Code: 0e 48 8d 7d 20 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 58 02 00 00 48 8b 55 20 4c 89 e6 48 c7 c7 20 67 15 8c e8 00 fa bb fc 90 <0f> 0b 90 48 83 c4 18 48 89 d8 5b 5d 41 5c 41 5d 41 5e 41 5f e9 31
RSP: 0018:ffffc9000b9df7b0 EFLAGS: 00010086
RAX: 0000000000000050 RBX: ffff888057c88d20 RCX: ffffffff819b01d9
RDX: 0000000000000000 RSI: ffffffff819b8066 RDI: 0000000000000005
RBP: ffff888068795a00 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000001 R11: 3d3d3d3d3d3d3d3d R12: ffffc9000b9dfa98
R13: ffff888068795a00 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88812475e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb3616f5052 CR3: 000000002930d000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 lookup_object_or_alloc lib/debugobjects.c:665 [inline]
 __debug_object_init+0x2a9/0x3d0 lib/debugobjects.c:743
 __init_work+0x4c/0x60 kernel/workqueue.c:677
 rhashtable_init_noprof+0x49f/0x7e0 lib/rhashtable.c:1085
 bch2_copygc_thread+0xf6/0xdd0 fs/bcachefs/movinggc.c:353
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>