drm/vmwgfx: Fix a destoy-while-held mutex problem.

commit 73a88250b70954a8f27c2444e1c2411bba3c29d9 upstream.

When validating legacy surfaces, the backup bo might be destroyed at
surface validate time. However, the kms resource validation code may have
the bo reserved, so we will destroy a locked mutex. While there shouldn't
be any other users of that mutex when it is destroyed, it causes a lock
leak and thus throws a lockdep error.

Fix this by having the kms resource validation code hold a reference to
the bo while we have it reserved. We do this by introducing a validation
context which might come in handy when the kms code is extended to validate
multiple resources or buffers.

Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
index f823fc3efed7..3184a9ae22c1 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c
@@ -1003,12 +1003,13 @@ int vmw_kms_stdu_surface_dirty(struct vmw_private *dev_priv,
 	struct vmw_framebuffer_surface *vfbs =
 		container_of(framebuffer, typeof(*vfbs), base);
 	struct vmw_stdu_dirty sdirty;
+	struct vmw_validation_ctx ctx;
 	int ret;
 
 	if (!srf)
 		srf = &vfbs->surface->res;
 
-	ret = vmw_kms_helper_resource_prepare(srf, true);
+	ret = vmw_kms_helper_resource_prepare(srf, true, &ctx);
 	if (ret)
 		return ret;
 
@@ -1031,7 +1032,7 @@ int vmw_kms_stdu_surface_dirty(struct vmw_private *dev_priv,
 				   dest_x, dest_y, num_clips, inc,
 				   &sdirty.base);
 out_finish:
-	vmw_kms_helper_resource_finish(srf, out_fence);
+	vmw_kms_helper_resource_finish(&ctx, out_fence);
 
 	return ret;
 }