Looks good to me.
Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@xxxxxxxxxxxx>
On Tue, Jun 9, 2020 at 8:57 AM Venkata Lakshmi Narayana Gubba
<gubbaven@xxxxxxxxxxxxxx> wrote:
>
> Due to race conditions between qca_hw_error and qca_controller_memdump
> during SSR timeout,the same pointer is freed twice. This results in a
> double free. Now a lock is acquired before checking the stauts of SSR
> state.
>
> Fixes: d841502c79e3 ("Bluetooth: hci_qca: Collect controller memory dump during SSR")
> Signed-off-by: Venkata Lakshmi Narayana Gubba <gubbaven@xxxxxxxxxxxxxx>
> ---
> drivers/bluetooth/hci_qca.c | 29 +++++++++++++++++------------
> 1 file changed, 17 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 28c34a1..f3fde99 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -981,8 +981,11 @@ static void qca_controller_memdump(struct work_struct *work)
> while ((skb = skb_dequeue(&qca->rx_memdump_q))) {
>
> mutex_lock(&qca->hci_memdump_lock);
> - /* Skip processing the received packets if timeout detected. */
> - if (qca->memdump_state == QCA_MEMDUMP_TIMEOUT) {
> + /* Skip processing the received packets if timeout detected
> + * or memdump collection completed.
> + */
> + if (qca->memdump_state == QCA_MEMDUMP_TIMEOUT ||
> + qca->memdump_state == QCA_MEMDUMP_COLLECTED) {
> mutex_unlock(&qca->hci_memdump_lock);
> return;
> }
> @@ -1483,8 +1486,6 @@ static void qca_hw_error(struct hci_dev *hdev, u8 code)
> {
> struct hci_uart *hu = hci_get_drvdata(hdev);
> struct qca_data *qca = hu->priv;
> - struct qca_memdump_data *qca_memdump = qca->qca_memdump;
> - char *memdump_buf = NULL;
>
> set_bit(QCA_HW_ERROR_EVENT, &qca->flags);
> bt_dev_info(hdev, "mem_dump_status: %d", qca->memdump_state);
> @@ -1507,19 +1508,23 @@ static void qca_hw_error(struct hci_dev *hdev, u8 code)
> qca_wait_for_dump_collection(hdev);
> }
>
> + mutex_lock(&qca->hci_memdump_lock);
> if (qca->memdump_state != QCA_MEMDUMP_COLLECTED) {
> bt_dev_err(hu->hdev, "clearing allocated memory due to memdump timeout");
> - mutex_lock(&qca->hci_memdump_lock);
> - if (qca_memdump)
> - memdump_buf = qca_memdump->memdump_buf_head;
> - vfree(memdump_buf);
> - kfree(qca_memdump);
> - qca->qca_memdump = NULL;
> + if (qca->qca_memdump) {
> + vfree(qca->qca_memdump->memdump_buf_head);
> + kfree(qca->qca_memdump);
> + qca->qca_memdump = NULL;
> + }
> qca->memdump_state = QCA_MEMDUMP_TIMEOUT;
> cancel_delayed_work(&qca->ctrl_memdump_timeout);
> - skb_queue_purge(&qca->rx_memdump_q);
> - mutex_unlock(&qca->hci_memdump_lock);
> + }
> + mutex_unlock(&qca->hci_memdump_lock);
> +
> + if (qca->memdump_state == QCA_MEMDUMP_TIMEOUT ||
> + qca->memdump_state == QCA_MEMDUMP_COLLECTED) {
> cancel_work_sync(&qca->ctrl_memdump_evt);
> + skb_queue_purge(&qca->rx_memdump_q);
> }
>
> clear_bit(QCA_HW_ERROR_EVENT, &qca->flags);
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>
