From fcee337704d76446e0d4714cc5eff53e896f7c6f Mon Sep 17 00:00:00 2001 From: Gustavo Padovan Date: Thu, 11 Jul 2013 11:34:28 +0100 Subject: [PATCH] Bluetooth: Fix race between hci_register_dev() and hci_dev_open() If hci_dev_open() is called after hci_register_dev() added the device to the hci_dev_list but before the workqueue are created we could run into a NULL pointer dereference (see below). This bug is very unlikely to happen, systems using bluetoothd to manage their bluetooth devices will never see this happen. BUG: unable to handle kernel NULL pointer dereference 0100 IP: [] __queue_work+0x32/0x3d0 (...) Call Trace: [] queue_work_on+0x45/0x50 [] hci_req_run+0xbf/0xf0 [bluetooth] [] ? hci_init2_req+0x720/0x720 [bluetooth] [] __hci_req_sync+0xd6/0x1c0 [bluetooth] [] ? try_to_wake_up+0x2b0/0x2b0 [] ? usb_autopm_put_interface+0x30/0x40 [] hci_dev_open+0x275/0x2e0 [bluetooth] [] hci_sock_ioctl+0x1f2/0x3f0 [bluetooth] [] sock_do_ioctl+0x30/0x70 [] sock_ioctl+0x79/0x2f0 [] do_vfs_ioctl+0x96/0x560 [] SyS_ioctl+0x91/0xb0 [] system_call_fastpath+0x1a/0x1f Reported-by: Sedat Dilek Signed-off-by: Gustavo Padovan --- net/bluetooth/hci_core.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index ace5e55fe5a3..64d33d1e14c8 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -2207,10 +2207,6 @@ int hci_register_dev(struct hci_dev *hdev) BT_DBG("%p name %s bus %d", hdev, hdev->name, hdev->bus); - write_lock(&hci_dev_list_lock); - list_add(&hdev->list, &hci_dev_list); - write_unlock(&hci_dev_list_lock); - hdev->workqueue = alloc_workqueue(hdev->name, WQ_HIGHPRI | WQ_UNBOUND | WQ_MEM_RECLAIM, 1); if (!hdev->workqueue) { @@ -2246,6 +2242,10 @@ int hci_register_dev(struct hci_dev *hdev) if (hdev->dev_type != HCI_AMP) set_bit(HCI_AUTO_OFF, &hdev->dev_flags); + write_lock(&hci_dev_list_lock); + list_add(&hdev->list, &hci_dev_list); + write_unlock(&hci_dev_list_lock); + hci_notify(hdev, HCI_DEV_REG); hci_dev_hold(hdev); @@ -2258,9 +2258,6 @@ err_wqueue: destroy_workqueue(hdev->req_workqueue); err: ida_simple_remove(&hci_index_ida, hdev->id); - write_lock(&hci_dev_list_lock); - list_del(&hdev->list); - write_unlock(&hci_dev_list_lock); return error; } -- 2.30.2