cgroup: fork rejected by pids controller in /syz3
======================================================
WARNING: possible circular locking dependency detected
5.15.111-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor343/3976 is trying to acquire lock:
ffff0000d7352120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1649 [inline]
ffff0000d7352120 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_conn_del+0xf0/0x4cc net/bluetooth/sco.c:196

but task is already holding lock:
ffff800016af9528 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1518 [inline]
ffff800016af9528 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x208 net/bluetooth/hci_conn.c:1610

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (hci_cb_list_lock){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
       hci_connect_cfm include/net/bluetooth/hci_core.h:1503 [inline]
       hci_remote_features_evt+0x480/0x928 net/bluetooth/hci_event.c:3323
       hci_event_packet+0x5d4/0x1258 net/bluetooth/hci_event.c:6376
       hci_rx_work+0x1d0/0x6d0 net/bluetooth/hci_core.c:5153
       process_one_work+0x790/0x11b8 kernel/workqueue.c:2307
       worker_thread+0x910/0x1034 kernel/workqueue.c:2454
       kthread+0x37c/0x45c kernel/kthread.c:319
       ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:870

-> #1 (&hdev->lock){+.+.}-{3:3}:
       __mutex_lock_common+0x194/0x2154 kernel/locking/mutex.c:596
       __mutex_lock kernel/locking/mutex.c:729 [inline]
       mutex_lock_nested+0xa4/0xf8 kernel/locking/mutex.c:743
       sco_sock_connect+0x170/0x834 net/bluetooth/sco.c:587
       __sys_connect_file net/socket.c:1899 [inline]
       __sys_connect+0x268/0x290 net/socket.c:1916
       __do_sys_connect net/socket.c:1926 [inline]
       __se_sys_connect net/socket.c:1923 [inline]
       __arm64_sys_connect+0x7c/0x94 net/socket.c:1923
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3787 [inline]
       __lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
       lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
       lock_sock_nested+0xec/0x1ec net/core/sock.c:3216
       lock_sock include/net/sock.h:1649 [inline]
       sco_conn_del+0xf0/0x4cc net/bluetooth/sco.c:196
       sco_disconn_cfm+0x8c/0xdc net/bluetooth/sco.c:1208
       hci_disconn_cfm include/net/bluetooth/hci_core.h:1521 [inline]
       hci_conn_hash_flush+0x104/0x208 net/bluetooth/hci_conn.c:1610
       hci_dev_do_close+0x7e4/0x1020 net/bluetooth/hci_core.c:1795
       hci_unregister_dev+0x228/0x48c net/bluetooth/hci_core.c:4033
       vhci_release+0x74/0xc4 drivers/bluetooth/hci_vhci.c:342
       __fput+0x30c/0x7f0 fs/file_table.c:280
       ____fput+0x20/0x30 fs/file_table.c:308
       task_work_run+0x130/0x1e4 kernel/task_work.c:164
       exit_task_work include/linux/task_work.h:32 [inline]
       do_exit+0x688/0x2134 kernel/exit.c:872
       do_group_exit+0x110/0x268 kernel/exit.c:994
       __do_sys_exit_group kernel/exit.c:1005 [inline]
       __se_sys_exit_group kernel/exit.c:1003 [inline]
       __wake_up_parent+0x0/0x60 kernel/exit.c:1003
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

Chain exists of:
  sk_lock-AF_BLUETOOTH-BTPROTO_SCO --> &hdev->lock --> hci_cb_list_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(hci_cb_list_lock);
                               lock(&hdev->lock);
                               lock(hci_cb_list_lock);
  lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);

 *** DEADLOCK ***

3 locks held by syz-executor343/3976:
 #0: ffff0000c80c0ff0 (&hdev->req_lock){+.+.}-{3:3}, at: hci_dev_do_close+0x64/0x1020 net/bluetooth/hci_core.c:1737
 #1: ffff0000c80c0078 (&hdev->lock){+.+.}-{3:3}, at: hci_dev_do_close+0x338/0x1020 net/bluetooth/hci_core.c:1782
 #2: ffff800016af9528 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:1518 [inline]
 #2: ffff800016af9528 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_conn_hash_flush+0xb8/0x208 net/bluetooth/hci_conn.c:1610

stack backtrace:
CPU: 0 PID: 3976 Comm: syz-executor343 Not tainted 5.15.111-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3787 [inline]
 __lock_acquire+0x32cc/0x7620 kernel/locking/lockdep.c:5011
 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5622
 lock_sock_nested+0xec/0x1ec net/core/sock.c:3216
 lock_sock include/net/sock.h:1649 [inline]
 sco_conn_del+0xf0/0x4cc net/bluetooth/sco.c:196
 sco_disconn_cfm+0x8c/0xdc net/bluetooth/sco.c:1208
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1521 [inline]
 hci_conn_hash_flush+0x104/0x208 net/bluetooth/hci_conn.c:1610
 hci_dev_do_close+0x7e4/0x1020 net/bluetooth/hci_core.c:1795
 hci_unregister_dev+0x228/0x48c net/bluetooth/hci_core.c:4033
 vhci_release+0x74/0xc4 drivers/bluetooth/hci_vhci.c:342
 __fput+0x30c/0x7f0 fs/file_table.c:280
 ____fput+0x20/0x30 fs/file_table.c:308
 task_work_run+0x130/0x1e4 kernel/task_work.c:164
 exit_task_work include/linux/task_work.h:32 [inline]
 do_exit+0x688/0x2134 kernel/exit.c:872
 do_group_exit+0x110/0x268 kernel/exit.c:994
 __do_sys_exit_group kernel/exit.c:1005 [inline]
 __se_sys_exit_group kernel/exit.c:1003 [inline]
 __wake_up_parent+0x0/0x60 kernel/exit.c:1003
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:596
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:614
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584