| Message ID | 1573025467-18278-1-git-send-email-bianpan2016@163.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/i915/gvt: fix dropping obj reference twice | expand |
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:
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@163.com> --- drivers/gpu/drm/i915/gvt/dmabuf.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)