syzbot

======================================================
WARNING: possible circular locking dependency detected
6.14.0-rc6-syzkaller-00003-g4d872d51bc9d #0 Not tainted
------------------------------------------------------
kworker/u9:8/5839 is trying to acquire lock:
ffff88805acd3258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1624 [inline]
ffff88805acd3258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_ready net/bluetooth/sco.c:1341 [inline]
ffff88805acd3258 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_connect_cfm+0x439/0xae0 net/bluetooth/sco.c:1415

but task is already holding lock:
ffff8880334b4620 (&conn->lock#3){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff8880334b4620 (&conn->lock#3){+.+.}-{3:3}, at: sco_conn_ready net/bluetooth/sco.c:1328 [inline]
ffff8880334b4620 (&conn->lock#3){+.+.}-{3:3}, at: sco_connect_cfm+0x262/0xae0 net/bluetooth/sco.c:1415

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&conn->lock#3){+.+.}-{3:3}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
       _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
       spin_lock include/linux/spinlock.h:351 [inline]
       sco_chan_add net/bluetooth/sco.c:292 [inline]
       sco_connect net/bluetooth/sco.c:348 [inline]
       sco_sock_connect+0x34c/0x9b0 net/bluetooth/sco.c:648
       __sys_connect_file net/socket.c:2045 [inline]
       __sys_connect+0x288/0x2d0 net/socket.c:2064
       __do_sys_connect net/socket.c:2070 [inline]
       __se_sys_connect net/socket.c:2067 [inline]
       __x64_sys_connect+0x7a/0x90 net/socket.c:2067
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
       __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
       lock_sock_nested+0x48/0x100 net/core/sock.c:3662
       lock_sock include/net/sock.h:1624 [inline]
       sco_conn_ready net/bluetooth/sco.c:1341 [inline]
       sco_connect_cfm+0x439/0xae0 net/bluetooth/sco.c:1415
       hci_connect_cfm include/net/bluetooth/hci_core.h:2051 [inline]
       hci_conn_request_evt+0x8e9/0xf00 net/bluetooth/hci_event.c:3328
       hci_event_func net/bluetooth/hci_event.c:7473 [inline]
       hci_event_packet+0xac1/0x1540 net/bluetooth/hci_event.c:7525
       hci_rx_work+0x3f3/0xdb0 net/bluetooth/hci_core.c:4015
       process_one_work kernel/workqueue.c:3238 [inline]
       process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
       worker_thread+0x870/0xd30 kernel/workqueue.c:3400
       kthread+0x7a9/0x920 kernel/kthread.c:464
       ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&conn->lock#3);
                               lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);
                               lock(&conn->lock#3);
  lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

 *** DEADLOCK ***

3 locks held by kworker/u9:8/5839:
 #0: ffff88807c01c148 ((wq_completion)hci1#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3213 [inline]
 #0: ffff88807c01c148 ((wq_completion)hci1#2){+.+.}-{0:0}, at: process_scheduled_works+0x98b/0x18e0 kernel/workqueue.c:3319
 #1: ffffc90004377c60 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3214 [inline]
 #1: ffffc90004377c60 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9c6/0x18e0 kernel/workqueue.c:3319
 #2: ffff8880334b4620 (&conn->lock#3){+.+.}-{3:3}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #2: ffff8880334b4620 (&conn->lock#3){+.+.}-{3:3}, at: sco_conn_ready net/bluetooth/sco.c:1328 [inline]
 #2: ffff8880334b4620 (&conn->lock#3){+.+.}-{3:3}, at: sco_connect_cfm+0x262/0xae0 net/bluetooth/sco.c:1415

stack backtrace:
CPU: 1 UID: 0 PID: 5839 Comm: kworker/u9:8 Not tainted 6.14.0-rc6-syzkaller-00003-g4d872d51bc9d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: hci1 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2076
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3906
 __lock_acquire+0x1397/0x2100 kernel/locking/lockdep.c:5228
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5851
 lock_sock_nested+0x48/0x100 net/core/sock.c:3662
 lock_sock include/net/sock.h:1624 [inline]
 sco_conn_ready net/bluetooth/sco.c:1341 [inline]
 sco_connect_cfm+0x439/0xae0 net/bluetooth/sco.c:1415
 hci_connect_cfm include/net/bluetooth/hci_core.h:2051 [inline]
 hci_conn_request_evt+0x8e9/0xf00 net/bluetooth/hci_event.c:3328
 hci_event_func net/bluetooth/hci_event.c:7473 [inline]
 hci_event_packet+0xac1/0x1540 net/bluetooth/hci_event.c:7525
 hci_rx_work+0x3f3/0xdb0 net/bluetooth/hci_core.c:4015
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
BUG: sleeping function called from invalid context at net/core/sock.c:3664
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 5839, name: kworker/u9:8
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
INFO: lockdep is turned off.
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 1 UID: 0 PID: 5839 Comm: kworker/u9:8 Not tainted 6.14.0-rc6-syzkaller-00003-g4d872d51bc9d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: hci1 hci_rx_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 __might_resched+0x5d4/0x780 kernel/sched/core.c:8767
 lock_sock_nested+0x5d/0x100 net/core/sock.c:3664
 lock_sock include/net/sock.h:1624 [inline]
 sco_conn_ready net/bluetooth/sco.c:1341 [inline]
 sco_connect_cfm+0x439/0xae0 net/bluetooth/sco.c:1415
 hci_connect_cfm include/net/bluetooth/hci_core.h:2051 [inline]
 hci_conn_request_evt+0x8e9/0xf00 net/bluetooth/hci_event.c:3328
 hci_event_func net/bluetooth/hci_event.c:7473 [inline]
 hci_event_packet+0xac1/0x1540 net/bluetooth/hci_event.c:7525
 hci_rx_work+0x3f3/0xdb0 net/bluetooth/hci_core.c:4015
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0xabe/0x18e0 kernel/workqueue.c:3319
 worker_thread+0x870/0xd30 kernel/workqueue.c:3400
 kthread+0x7a9/0x920 kernel/kthread.c:464
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>