[PATCH] drm/i915/gvt: return error when failing to take the module reference

[PATCH] drm/i915/gvt: return error when failing to take the module reference

[Xiongfeng Wang]

When we fail to take the module reference, we go to the 'undo*' branch and
return. But the returned variable 'ret' has been set as zero by the
above code. Change 'ret' to '-ENODEV' in this situation.

Fixes: 9bdb073464d6 ("drm/i915/gvt: Change KVMGT as self load module")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
---
 drivers/gpu/drm/i915/gvt/kvmgt.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index ad8a9df..778eb8c 100644
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -829,8 +829,10 @@ static int intel_vgpu_open(struct mdev_device *mdev)
 	/* Take a module reference as mdev core doesn't take
 	 * a reference for vendor driver.
 	 */
-	if (!try_module_get(THIS_MODULE))
+	if (!try_module_get(THIS_MODULE)) {
+		ret = -ENODEV;
 		goto undo_group;
+	}
 
 	ret = kvmgt_guest_init(mdev);
 	if (ret)
-- 
1.7.12.4

Re: [PATCH] drm/i915/gvt: return error when failing to take the module reference

[Zhenyu Wang]

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On 2020.11.12 21:22:32 +0800, Xiongfeng Wang wrote:
> When we fail to take the module reference, we go to the 'undo*' branch and
> return. But the returned variable 'ret' has been set as zero by the
> above code. Change 'ret' to '-ENODEV' in this situation.
> 
> Fixes: 9bdb073464d6 ("drm/i915/gvt: Change KVMGT as self load module")
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
> ---
>  drivers/gpu/drm/i915/gvt/kvmgt.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index ad8a9df..778eb8c 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -829,8 +829,10 @@ static int intel_vgpu_open(struct mdev_device *mdev)
>  	/* Take a module reference as mdev core doesn't take
>  	 * a reference for vendor driver.
>  	 */
> -	if (!try_module_get(THIS_MODULE))
> +	if (!try_module_get(THIS_MODULE)) {
> +		ret = -ENODEV;
>  		goto undo_group;
> +	}
>  
>  	ret = kvmgt_guest_init(mdev);
>  	if (ret)
> -- 

Thanks for the fix!

Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>

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