mei: fix NULL dereferencing during FW initiated disconnection

In the case when disconnection is initiated from the FW
the driver is flushing items from the write control list while
iterating over it:

mei_irq_write_handler()
    list_for_each_entry_safe(ctrl_wr_list)         <-- outer loop
         mei_cl_irq_disconnect_rsp()
             mei_cl_set_disconnected()
                 mei_io_list_flush(ctrl_wr_list)   <-- destorying list

We move the list flushing to the completion routine.

Cc: <stable@vger.kernel.org> #4.2+
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index bab17e4197b68b4763bf05a92d14ffffbaf70f4a..09f5280fa021f9f593cfd493075f463ba8c8a768 100644 (file)
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -1766,6 +1766,10 @@ void mei_cl_complete(struct mei_cl *cl, struct mei_cl_cb *cb)
                if (waitqueue_active(&cl->wait))
                        wake_up(&cl->wait);
 
+               break;
+       case MEI_FOP_DISCONNECT_RSP:
+               mei_io_cb_free(cb);
+               mei_cl_set_disconnected(cl);
                break;
        default:
                BUG_ON(0);

diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
index 5eaa4638e824f7dab10260b2c318147cdd45ec3e..5aa606c8a827ae14df65de84f77d05ec4db252f2 100644 (file)
--- a/drivers/misc/mei/hbm.c
+++ b/drivers/misc/mei/hbm.c
@@ -877,8 +877,7 @@ static int mei_hbm_fw_disconnect_req(struct mei_device *dev,
                cb = mei_io_cb_init(cl, MEI_FOP_DISCONNECT_RSP, NULL);
                if (!cb)
                        return -ENOMEM;
-               cl_dbg(dev, cl, "add disconnect response as first\n");
-               list_add(&cb->list, &dev->ctrl_wr_list.list);
+               list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
        }
        return 0;
 }

diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index 1e5cb1f704f809d56c350969953567e091203227..704dc6caad6d783ac321d0ea9c7ccf881191bcb3 100644 (file)
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -194,10 +194,7 @@ static int mei_cl_irq_disconnect_rsp(struct mei_cl *cl, struct mei_cl_cb *cb,
                return -EMSGSIZE;
 
        ret = mei_hbm_cl_disconnect_rsp(dev, cl);
-       mei_cl_set_disconnected(cl);
-       mei_io_cb_free(cb);
-       mei_me_cl_put(cl->me_cl);
-       cl->me_cl = NULL;
+       list_move_tail(&cb->list, &cmpl_list->list);
 
        return ret;
 }