[PATCH v1] usb: usbfs: fix double-free of usb memory upon submiturb error

[PATCH v1] usb: usbfs: fix double-free of usb memory upon submiturb error

[gavinli]

From: Gavin Li <git@thegavinli.com>

Upon an error within proc_do_submiturb(), dec_usb_memory_use_count()
gets called once by the error handling tail and again by free_async().
Remove the first call.

Signed-off-by: Gavin Li <git@thegavinli.com>
---
 drivers/usb/core/devio.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index fa783531ee88..f026a0d54ce5 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1789,8 +1789,6 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
 	return 0;
 
  error:
-	if (as && as->usbm)
-		dec_usb_memory_use_count(as->usbm, &as->usbm->urb_use_count);
 	kfree(isopkt);
 	kfree(dr);
 	if (as)
-- 
2.22.0

Re: [PATCH v1] usb: usbfs: fix double-free of usb memory upon submiturb error

[Alan Stern]

On Sun, 4 Aug 2019 gavinli@thegavinli.com wrote:

> From: Gavin Li <git@thegavinli.com>
> 
> Upon an error within proc_do_submiturb(), dec_usb_memory_use_count()
> gets called once by the error handling tail and again by free_async().
> Remove the first call.
> 
> Signed-off-by: Gavin Li <git@thegavinli.com>
> ---
>  drivers/usb/core/devio.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
> index fa783531ee88..f026a0d54ce5 100644
> --- a/drivers/usb/core/devio.c
> +++ b/drivers/usb/core/devio.c
> @@ -1789,8 +1789,6 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
>  	return 0;
>  
>   error:
> -	if (as && as->usbm)
> -		dec_usb_memory_use_count(as->usbm, &as->usbm->urb_use_count);
>  	kfree(isopkt);
>  	kfree(dr);
>  	if (as)

Acked-by: Alan Stern <stern@rowland.harvard.edu>