3.16.37-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Takashi Iwai <[email protected]> commit c7c999cb18da88a881e10e07f0724ad0bfaff770 upstream. hci_vhci driver creates a hci device object dynamically upon each HCI_VENDOR_PKT write. Although it checks the already created object and returns an error, it's still racy and may build multiple hci_dev objects concurrently when parallel writes are performed, as the device tracks only a single hci_dev object. This patch introduces a mutex to protect against the concurrent device creations. Signed-off-by: Takashi Iwai <[email protected]> Signed-off-by: Marcel Holtmann <[email protected]> [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings <[email protected]> --- drivers/bluetooth/hci_vhci.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) --- a/drivers/bluetooth/hci_vhci.c +++ b/drivers/bluetooth/hci_vhci.c @@ -50,6 +50,7 @@ struct vhci_data { wait_queue_head_t read_wait; struct sk_buff_head readq; + struct mutex open_mutex; struct delayed_work open_timeout; }; @@ -95,11 +96,14 @@ static int vhci_send_frame(struct hci_de return 0; } -static int vhci_create_device(struct vhci_data *data, __u8 dev_type) +static int __vhci_create_device(struct vhci_data *data, __u8 dev_type) { struct hci_dev *hdev; struct sk_buff *skb; + if (data->hdev) + return -EBADFD; + skb = bt_skb_alloc(4, GFP_KERNEL); if (!skb) return -ENOMEM; @@ -140,6 +144,17 @@ static int vhci_create_device(struct vhc return 0; } +static int vhci_create_device(struct vhci_data *data, __u8 opcode) +{ + int err; + + mutex_lock(&data->open_mutex); + err = __vhci_create_device(data, opcode); + mutex_unlock(&data->open_mutex); + + return err; +} + static inline ssize_t vhci_get_user(struct vhci_data *data, const struct iovec *iov, unsigned long count) @@ -185,11 +200,6 @@ static inline ssize_t vhci_get_user(stru case HCI_VENDOR_PKT: cancel_delayed_work_sync(&data->open_timeout); - if (data->hdev) { - kfree_skb(skb); - return -EBADFD; - } - dev_type = *((__u8 *) skb->data); skb_pull(skb, 1); @@ -318,6 +328,7 @@ static int vhci_open(struct inode *inode skb_queue_head_init(&data->readq); init_waitqueue_head(&data->read_wait); + mutex_init(&data->open_mutex); INIT_DELAYED_WORK(&data->open_timeout, vhci_open_timeout); file->private_data = data;
