[PATCH 2/6] drm/vmwgfx: Fix user space handle equal to zero

Thomas Hellstrom thellstrom at vmware.com
Tue May 21 08:24:35 UTC 2019


User-space handles equal to zero are interpreted as uninitialized or
illegal by some drm systems (most notably kms). This means that a
dumb buffer or surface with a zero user-space handle can never be
used as a kms frame-buffer.

Cc: <stable at vger.kernel.org>
Fixes: c7eae62666ad ("drm/vmwgfx: Make the object handles idr-generated")
Signed-off-by: Thomas Hellstrom <thellstrom at vmware.com>
Reviewed-by: Deepak Rawat <drawat at vmware.com>
---
 drivers/gpu/drm/vmwgfx/ttm_object.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vmwgfx/ttm_object.c b/drivers/gpu/drm/vmwgfx/ttm_object.c
index 36990b80e790..16077785ad47 100644
--- a/drivers/gpu/drm/vmwgfx/ttm_object.c
+++ b/drivers/gpu/drm/vmwgfx/ttm_object.c
@@ -174,7 +174,7 @@ int ttm_base_object_init(struct ttm_object_file *tfile,
 	kref_init(&base->refcount);
 	idr_preload(GFP_KERNEL);
 	spin_lock(&tdev->object_lock);
-	ret = idr_alloc(&tdev->idr, base, 0, 0, GFP_NOWAIT);
+	ret = idr_alloc(&tdev->idr, base, 1, 0, GFP_NOWAIT);
 	spin_unlock(&tdev->object_lock);
 	idr_preload_end();
 	if (ret < 0)
-- 
2.20.1



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