[PATCH] hisi_acc_vfio_pci: Fix reference leak in hisi_acc_vfio_debug_init

[PATCH] hisi_acc_vfio_pci: Fix reference leak in hisi_acc_vfio_debug_init

[Miaoqian Lin]

The debugfs_lookup() function returns a dentry with an increased reference
count that must be released by calling dput().

Fixes: b398f91779b8 ("hisi_acc_vfio_pci: register debugfs for hisilicon migration driver")
Cc: stable@vger.kernel.org
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
---
 drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
index 2149f49aeec7..1710485cbbec 100644
--- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
+++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
@@ -1611,8 +1611,10 @@ static void hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vd
 	}
 
 	migf = kzalloc(sizeof(*migf), GFP_KERNEL);
-	if (!migf)
+	if (!migf) {
+		dput(vfio_dev_migration);
 		return;
+	}
 	hisi_acc_vdev->debug_migf = migf;
 
 	vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration);
@@ -1622,6 +1624,8 @@ static void hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vd
 				    hisi_acc_vf_migf_read);
 	debugfs_create_devm_seqfile(dev, "cmd_state", vfio_hisi_acc,
 				    hisi_acc_vf_debug_cmd);
+
+	dput(vfio_dev_migration);
 }
 
 static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
-- 
2.35.1

Re: [PATCH] hisi_acc_vfio_pci: Fix reference leak in hisi_acc_vfio_debug_init

[liulongfang]

On 2025/9/1 16:18, Miaoqian Lin wrote:
> The debugfs_lookup() function returns a dentry with an increased reference
> count that must be released by calling dput().
> 
> Fixes: b398f91779b8 ("hisi_acc_vfio_pci: register debugfs for hisilicon migration driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
> ---
>  drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index 2149f49aeec7..1710485cbbec 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -1611,8 +1611,10 @@ static void hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vd
>  	}
>  
>  	migf = kzalloc(sizeof(*migf), GFP_KERNEL);
> -	if (!migf)
> +	if (!migf) {
> +		dput(vfio_dev_migration);
>  		return;
> +	}
>  	hisi_acc_vdev->debug_migf = migf;
>  
>  	vfio_hisi_acc = debugfs_create_dir("hisi_acc", vfio_dev_migration);
> @@ -1622,6 +1624,8 @@ static void hisi_acc_vfio_debug_init(struct hisi_acc_vf_core_device *hisi_acc_vd
>  				    hisi_acc_vf_migf_read);
>  	debugfs_create_devm_seqfile(dev, "cmd_state", vfio_hisi_acc,
>  				    hisi_acc_vf_debug_cmd);
> +
> +	dput(vfio_dev_migration);
>  }
>

Reviewed-by: Longfang Liu <liulongfang@huawei.com>

Thanks!
Longfang.

>  static void hisi_acc_vf_debugfs_exit(struct hisi_acc_vf_core_device *hisi_acc_vdev)
> 

Re: [PATCH] hisi_acc_vfio_pci: Fix reference leak in hisi_acc_vfio_debug_init

[Markus Elfring]

> The debugfs_lookup() function returns a dentry with an increased reference
> count that must be released by calling dput().

* See also:
  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.17-rc4#n94

* Would you like to complete the object clean-up by using a goto chain?

* How do you think about to increase the application of scope-based resource management?
  https://elixir.bootlin.com/linux/v6.17-rc4/source/include/linux/pci.h#L1208

* Would it be helpful to append parentheses to the function name
  in the summary phrase?


Regards,
Markus