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Bluetooth: SCO: Fix possible circular locking dependency sco_sock_getsockopt

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This attempts to fix the following trace:

======================================================
WARNING: possible circular locking dependency detected
6.3.0-rc2-g68fcb3a7bf97 #4706 Not tainted
------------------------------------------------------
sco-tester/31 is trying to acquire lock:
ffff8880025b8070 (&hdev->lock){+.+.}-{3:3}, at:
sco_sock_getsockopt+0x1fc/0xa90

but task is already holding lock:
ffff888001eeb130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at:
sco_sock_getsockopt+0x104/0xa90

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
       lock_sock_nested+0x32/0x80
       sco_connect_cfm+0x118/0x4a0
       hci_sync_conn_complete_evt+0x1e6/0x3d0
       hci_event_packet+0x55c/0x7c0
       hci_rx_work+0x34c/0xa00
       process_one_work+0x575/0x910
       worker_thread+0x89/0x6f0
       kthread+0x14e/0x180
       ret_from_fork+0x2b/0x50

-> #1 (hci_cb_list_lock){+.+.}-{3:3}:
       __mutex_lock+0x13b/0xcc0
       hci_sync_conn_complete_evt+0x1ad/0x3d0
       hci_event_packet+0x55c/0x7c0
       hci_rx_work+0x34c/0xa00
       process_one_work+0x575/0x910
       worker_thread+0x89/0x6f0
       kthread+0x14e/0x180
       ret_from_fork+0x2b/0x50

-> #0 (&hdev->lock){+.+.}-{3:3}:
       __lock_acquire+0x18cc/0x3740
       lock_acquire+0x151/0x3a0
       __mutex_lock+0x13b/0xcc0
       sco_sock_getsockopt+0x1fc/0xa90
       __sys_getsockopt+0xe9/0x190
       __x64_sys_getsockopt+0x5b/0x70
       do_syscall_64+0x42/0x90
       entry_SYSCALL_64_after_hwframe+0x70/0xda

other info that might help us debug this:

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

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

1 lock held by sco-tester/31:
 #0: ffff888001eeb130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0},
 at: sco_sock_getsockopt+0x104/0xa90

Fixes: 248733e87d ("Bluetooth: Allow querying of supported offload codecs over SCO socket")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
This commit is contained in:
Luiz Augusto von Dentz 2023-03-30 14:45:03 -07:00
parent 9a8ec9e8eb
commit 975abc0c90
1 changed files with 9 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
net/bluetooth/sco.c
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@ -1140,6 +1140,8 @@ static int sco_sock_getsockopt(struct socket *sock, int level, int optname,
break;
}
release_sock(sk);
/* find total buffer size required to copy codec + caps */
hci_dev_lock(hdev);
list_for_each_entry(c, &hdev->local_codecs, list) {
@ -1157,15 +1159,13 @@ static int sco_sock_getsockopt(struct socket *sock, int level, int optname,
buf_len += sizeof(struct bt_codecs);
if (buf_len > len) {
hci_dev_put(hdev);
err = -ENOBUFS;
break;
return -ENOBUFS;
}
ptr = optval;
if (put_user(num_codecs, ptr)) {
hci_dev_put(hdev);
err = -EFAULT;
break;
return -EFAULT;
}
ptr += sizeof(num_codecs);
@ -1205,12 +1205,14 @@ static int sco_sock_getsockopt(struct socket *sock, int level, int optname,
ptr += len;
}
if (!err && put_user(buf_len, optlen))
err = -EFAULT;
hci_dev_unlock(hdev);
hci_dev_put(hdev);
lock_sock(sk);
if (!err && put_user(buf_len, optlen))
err = -EFAULT;
break;
default: