Patch "drm/dp/mst: take lock around looking up the branch device on hpd irq" has been added to the 4.1-stable tree

Patch "drm/dp/mst: take lock around looking up the branch device on hpd irq" has been added to the 4.1-stable tree

[gregkh]

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

    drm/dp/mst: take lock around looking up the branch device on hpd irq

to the 4.1-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:
     drm-dp-mst-take-lock-around-looking-up-the-branch-device-on-hpd-irq.patch
and it can be found in the queue-4.1 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 9eb1e57f564d4e6e10991402726cc83fe0b9172f Mon Sep 17 00:00:00 2001
From: Dave Airlie <airlied@redhat.com>
Date: Mon, 22 Jun 2015 14:40:44 +1000
Subject: drm/dp/mst: take lock around looking up the branch device on hpd irq

From: Dave Airlie <airlied@redhat.com>

commit 9eb1e57f564d4e6e10991402726cc83fe0b9172f upstream.

If we are doing an MST transaction and we've gotten HPD and we
lookup the device from the incoming msg, we should take the mgr
lock around it, so that mst_primary and mstb->ports are valid.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/drm_dp_mst_topology.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1171,6 +1171,8 @@ static struct drm_dp_mst_branch *drm_dp_
 	struct drm_dp_mst_port *port;
 	int i;
 	/* find the port by iterating down */
+
+	mutex_lock(&mgr->lock);
 	mstb = mgr->mst_primary;
 
 	for (i = 0; i < lct - 1; i++) {
@@ -1190,6 +1192,7 @@ static struct drm_dp_mst_branch *drm_dp_
 		}
 	}
 	kref_get(&mstb->kref);
+	mutex_unlock(&mgr->lock);
 	return mstb;
 }
 


Patches currently in stable-queue which might be from airlied@redhat.com are

queue-4.1/drm-vgem-set-unique-to-vgem.patch
queue-4.1/drm-dp-mst-take-lock-around-looking-up-the-branch-device-on-hpd-irq.patch
queue-4.1/drm-dp-mst-make-sure-mst_primary-mstb-is-valid-in-work-function.patch
queue-4.1/drm-qxl-do-not-leak-memory-if-qxl_release_list_add-fails.patch
queue-4.1/drm-qxl-do-not-cause-spice-server-to-clean-our-objects.patch
queue-4.1/drm-dp-mst-close-deadlock-in-connector-destruction.patch