Patch "mei: bus: call mei_cl_read_start under device lock" has been added to the 4.6-stable tree

Patch "mei: bus: call mei_cl_read_start under device lock" has been added to the 4.6-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    mei: bus: call mei_cl_read_start under device lock

to the 4.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     mei-bus-call-mei_cl_read_start-under-device-lock.patch
and it can be found in the queue-4.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From bc46b45a421a64a0895dd41a34d3d2086e1ac7f6 Mon Sep 17 00:00:00 2001
From: Alexander Usyskin <alexander.usyskin@intel.com>
Date: Tue, 3 May 2016 18:54:21 -0400
Subject: mei: bus: call mei_cl_read_start under device lock

From: Alexander Usyskin <alexander.usyskin@intel.com>

commit bc46b45a421a64a0895dd41a34d3d2086e1ac7f6 upstream.

Ensure that mei_cl_read_start is called under the device lock
also in the bus layer. The function updates global ctrl_wr_list
which should be locked.

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>

---
 drivers/misc/mei/bus.c |   15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -220,17 +220,23 @@ EXPORT_SYMBOL_GPL(mei_cldev_recv);
 static void mei_cl_bus_event_work(struct work_struct *work)
 {
 	struct mei_cl_device *cldev;
+	struct mei_device *bus;
 
 	cldev = container_of(work, struct mei_cl_device, event_work);
 
+	bus = cldev->bus;
+
 	if (cldev->event_cb)
 		cldev->event_cb(cldev, cldev->events, cldev->event_context);
 
 	cldev->events = 0;
 
 	/* Prepare for the next read */
-	if (cldev->events_mask & BIT(MEI_CL_EVENT_RX))
+	if (cldev->events_mask & BIT(MEI_CL_EVENT_RX)) {
+		mutex_lock(&bus->device_lock);
 		mei_cl_read_start(cldev->cl, 0, NULL);
+		mutex_unlock(&bus->device_lock);
+	}
 }
 
 /**
@@ -304,6 +310,7 @@ int mei_cldev_register_event_cb(struct m
 				unsigned long events_mask,
 				mei_cldev_event_cb_t event_cb, void *context)
 {
+	struct mei_device *bus = cldev->bus;
 	int ret;
 
 	if (cldev->event_cb)
@@ -316,15 +323,17 @@ int mei_cldev_register_event_cb(struct m
 	INIT_WORK(&cldev->event_work, mei_cl_bus_event_work);
 
 	if (cldev->events_mask & BIT(MEI_CL_EVENT_RX)) {
+		mutex_lock(&bus->device_lock);
 		ret = mei_cl_read_start(cldev->cl, 0, NULL);
+		mutex_unlock(&bus->device_lock);
 		if (ret && ret != -EBUSY)
 			return ret;
 	}
 
 	if (cldev->events_mask & BIT(MEI_CL_EVENT_NOTIF)) {
-		mutex_lock(&cldev->cl->dev->device_lock);
+		mutex_lock(&bus->device_lock);
 		ret = mei_cl_notify_request(cldev->cl, NULL, event_cb ? 1 : 0);
-		mutex_unlock(&cldev->cl->dev->device_lock);
+		mutex_unlock(&bus->device_lock);
 		if (ret)
 			return ret;
 	}


Patches currently in stable-queue which might be from alexander.usyskin@intel.com are

queue-4.6/mei-fix-null-dereferencing-during-fw-initiated-disconnection.patch
queue-4.6/mei-amthif-discard-not-read-messages.patch
queue-4.6/mei-bus-call-mei_cl_read_start-under-device-lock.patch