diff mbox series

xen/xenbus: handle pointer to NULL in alloc/free_pdev

Message ID 20240529131926.29590-1-yskelg@gmail.com (mailing list archive)
State New, archived
Headers show
Series xen/xenbus: handle pointer to NULL in alloc/free_pdev | expand

Commit Message

Yunseong Kim May 29, 2024, 1:19 p.m. UTC 
From: Yunseong Kim <yskelg@gmail.com>

Modify 'alloc_pdev()' to set 'pdev->xdev' to NULL
if 'xen_pcibk_init_devices()' fails. This ensures that 'pdev->xdev' does
not point to 'xdev' when 'pdev' is freed.
And modify 'free_pdev()' to set 'pdev' to NULL.

Signed-off-by: Yunseong Kim <yskelg@gmail.com>
---
 drivers/xen/xen-pciback/xenbus.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Jürgen Groß May 29, 2024, 1:28 p.m. UTC | #1 
On 29.05.24 15:19, yskelg@gmail.com wrote:
> From: Yunseong Kim <yskelg@gmail.com>
> 
> Modify 'alloc_pdev()' to set 'pdev->xdev' to NULL
> if 'xen_pcibk_init_devices()' fails. This ensures that 'pdev->xdev' does
> not point to 'xdev' when 'pdev' is freed.
> And modify 'free_pdev()' to set 'pdev' to NULL.
> 
> Signed-off-by: Yunseong Kim <yskelg@gmail.com>
> ---
>   drivers/xen/xen-pciback/xenbus.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
> index b11e401f1b1e..f1709b8e284a 100644
> --- a/drivers/xen/xen-pciback/xenbus.c
> +++ b/drivers/xen/xen-pciback/xenbus.c
> @@ -54,6 +54,7 @@ static struct xen_pcibk_device *alloc_pdev(struct xenbus_device *xdev)
>   	INIT_WORK(&pdev->op_work, xen_pcibk_do_op);
>   
>   	if (xen_pcibk_init_devices(pdev)) {
> +		pdev->xdev = NULL;
>   		kfree(pdev);
>   		pdev = NULL;
>   	}
> @@ -102,6 +103,7 @@ static void free_pdev(struct xen_pcibk_device *pdev)
>   	pdev->xdev = NULL;
>   
>   	kfree(pdev);
> +	pdev = NULL;
>   }
>   
>   static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,

NAK!

Please stop that nonsense. NULL-ing pointers which have no chance to be used any
more is just adding code for no purpose at all.

Please don't send other iterations of this patch. You are wasting review
bandwidth.


Juergen
diff mbox series

Patch

diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c
index b11e401f1b1e..f1709b8e284a 100644
--- a/drivers/xen/xen-pciback/xenbus.c
+++ b/drivers/xen/xen-pciback/xenbus.c
@@ -54,6 +54,7 @@  static struct xen_pcibk_device *alloc_pdev(struct xenbus_device *xdev)
 	INIT_WORK(&pdev->op_work, xen_pcibk_do_op);
 
 	if (xen_pcibk_init_devices(pdev)) {
+		pdev->xdev = NULL;
 		kfree(pdev);
 		pdev = NULL;
 	}
@@ -102,6 +103,7 @@  static void free_pdev(struct xen_pcibk_device *pdev)
 	pdev->xdev = NULL;
 
 	kfree(pdev);
+	pdev = NULL;
 }
 
 static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref,