Patch "drm/msm: Take the mutex before calling msm_gem_new_impl" has been added to the 4.9-stable tree

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

drm/msm: Take the mutex before calling msm_gem_new_impl

to the 4.9-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-msm-take-the-mutex-before-calling-msm_gem_new_impl.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jordan Crouse <[email protected]>
Date: Mon, 8 May 2017 14:34:57 -0600
Subject: drm/msm: Take the mutex before calling msm_gem_new_impl

From: Jordan Crouse <[email protected]>

[ Upstream commit 90dd57de4a043f642179b1323a31ca3ced826611 ]

Amongst its other duties, msm_gem_new_impl adds the newly created GEM object to the shared inactive list which may also be actively modifiying the list during submission. All the paths to modify the list are protected by the mutex except for the one through msm_gem_import which can end up causing list corruption.

---
 drivers/gpu/drm/msm/msm_gem.c |    6 ++++++
 1 file changed, 6 insertions(+)

@@ -770,6 +770,8 @@ static int msm_gem_new_impl(struct drm_d
 	unsigned sz;
 	bool use_vram = false;
 
+	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
+
 	switch (flags & MSM_BO_CACHE_MASK) {
 	case MSM_BO_UNCACHED:
 	case MSM_BO_CACHED:

@@ -863,7 +865,11 @@ struct drm_gem_object *msm_gem_import(st
 
 	size = PAGE_ALIGN(dmabuf->size);
 
+	/* Take mutex so we can modify the inactive list in msm_gem_new_impl */
+	mutex_lock(&dev->struct_mutex);
 	ret = msm_gem_new_impl(dev, size, MSM_BO_WC, dmabuf->resv, &obj);
+	mutex_unlock(&dev->struct_mutex);
+
 	if (ret)
 		goto fail;
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/drm-msm-take-the-mutex-before-calling-msm_gem_new_impl.patch