[PATCH 1/2] drm/virtio: fix virtio_gpu_execbuffer_ioctl locking

[Gerd Hoffmann]

Lockdep says we can't call vmemdup() while having objects reserved
because it needs the mmap semaphore.  So reorder the calls reserve
the objects later.

Signed-off-by: Gerd Hoffmann <kra...@redhat.com>
---
 drivers/gpu/drm/virtio/virtgpu_ioctl.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c 
b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 205ec4abae2b..0477d1250f2d 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -126,22 +126,22 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device 
*dev, void *data,
                bo_handles = NULL;
        }
 
-       if (buflist) {
-               ret = virtio_gpu_array_lock_resv(buflist);
-               if (ret)
-                       goto out_unused_fd;
-       }
-
        buf = vmemdup_user(u64_to_user_ptr(exbuf->command), exbuf->size);
        if (IS_ERR(buf)) {
                ret = PTR_ERR(buf);
-               goto out_unresv;
+               goto out_unused_fd;
+       }
+
+       if (buflist) {
+               ret = virtio_gpu_array_lock_resv(buflist);
+               if (ret)
+                       goto out_memdup;
        }
 
        out_fence = virtio_gpu_fence_alloc(vgdev);
        if(!out_fence) {
                ret = -ENOMEM;
-               goto out_memdup;
+               goto out_unresv;
        }
 
        if (out_fence_fd >= 0) {
@@ -160,11 +160,11 @@ static int virtio_gpu_execbuffer_ioctl(struct drm_device 
*dev, void *data,
                              vfpriv->ctx_id, buflist, out_fence);
        return 0;
 
-out_memdup:
-       kvfree(buf);
 out_unresv:
        if (buflist)
                virtio_gpu_array_unlock_resv(buflist);
+out_memdup:
+       kvfree(buf);
 out_unused_fd:
        kvfree(bo_handles);
        if (buflist)
-- 
2.18.2

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