The reference count of obj will be decremented twice if error occurs
in dma_buf_fd(). Additionally, attempting to read the reference count of
obj after dropping reference may lead to a use after free bug. Here, we
drop obj's reference until it is not used.
Signed-off-by: Pan Bian <bianpan2016@xxxxxxx>
---
drivers/gpu/drm/i915/gvt/dmabuf.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/gvt/dmabuf.c b/drivers/gpu/drm/i915/gvt/dmabuf.c
index 13044c027f27..4bfaefdf548d 100644
--- a/drivers/gpu/drm/i915/gvt/dmabuf.c
+++ b/drivers/gpu/drm/i915/gvt/dmabuf.c
@@ -498,8 +498,6 @@ int intel_vgpu_get_dmabuf(struct intel_vgpu *vgpu, unsigned int dmabuf_id)
goto out_free_gem;
}
- i915_gem_object_put(obj);
-
ret = dma_buf_fd(dmabuf, DRM_CLOEXEC | DRM_RDWR);
if (ret < 0) {
gvt_vgpu_err("create dma-buf fd failed ret:%d\n", ret);
@@ -524,6 +522,8 @@ int intel_vgpu_get_dmabuf(struct intel_vgpu *vgpu, unsigned int dmabuf_id)
file_count(dmabuf->file),
kref_read(&obj->base.refcount));
+ i915_gem_object_put(obj);
+
return dmabuf_fd;
out_free_dmabuf:
--
2.7.4
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