Patch "drm/vmwgfx: Make sure backup_handle is always valid" has been added to the 4.4-stable tree

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

drm/vmwgfx: Make sure backup_handle is always valid

to the 4.4-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-vmwgfx-make-sure-backup_handle-is-always-valid.patch
and it can be found in the queue-4.4 subdirectory.

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

From: Sinclair Yeh <[email protected]>
Date: Fri, 2 Jun 2017 07:50:57 +0200
Subject: drm/vmwgfx: Make sure backup_handle is always valid

From: Sinclair Yeh <[email protected]>

commit 07678eca2cf9c9a18584e546c2b2a0d0c9a3150c upstream.

When vmw_gb_surface_define_ioctl() is called with an existing buffer, we end up returning an uninitialized variable in the backup_handle.

The fix is to first initialize backup_handle to 0 just to be sure, and second, when a user-provided buffer is found, we will use the req->buffer_handle as the backup_handle.

---
 drivers/gpu/drm/vmwgfx/vmwgfx_surface.c |   18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

@@ -1288,7 +1288,7 @@ int vmw_gb_surface_define_ioctl(struct d
 	struct ttm_object_file *tfile = vmw_fpriv(file_priv)->tfile;
 	int ret;
 	uint32_t size;
-	uint32_t backup_handle;
+	uint32_t backup_handle = 0;
 
 	if (req->multisample_count != 0)
 		return -EINVAL;

@@ -1331,12 +1331,16 @@ int vmw_gb_surface_define_ioctl(struct d
 		ret = vmw_user_dmabuf_lookup(tfile, req->buffer_handle,
 					     &res->backup,
 					     &user_srf->backup_base);
-		if (ret == 0 && res->backup->base.num_pages * PAGE_SIZE <
-		    res->backup_size) {
-			DRM_ERROR("Surface backup buffer is too small.\n");
-			vmw_dmabuf_unreference(&res->backup);
-			ret = -EINVAL;
-			goto out_unlock;
+		if (ret == 0) {
+			if (res->backup->base.num_pages * PAGE_SIZE <
+			    res->backup_size) {
+				DRM_ERROR("Surface backup buffer is too small.\n");
+				vmw_dmabuf_unreference(&res->backup);
+				ret = -EINVAL;
+				goto out_unlock;
+			} else {
+				backup_handle = req->buffer_handle;
+			}
 		}
 	} else if (req->drm_surface_flags & drm_vmw_surface_flag_create_buffer)
 		ret = vmw_user_dmabuf_alloc(dev_priv, tfile,

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

queue-4.4/drm-vmwgfx-limit-the-number-of-mip-levels-in-vmw_gb_surface_define_ioctl.patch queue-4.4/drm-vmwgfx-make-sure-backup_handle-is-always-valid.patch queue-4.4/drm-vmwgfx-handle-vmalloc-failure-in-vmw_local_fifo_reserve.patch