WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel][PATCH]: Fix some bugs in usbfront

To: Ky Srinivasan <ksrinivasan@xxxxxxxxxx>
Subject: Re: [Xen-devel][PATCH]: Fix some bugs in usbfront
From: Pasi Kärkkäinen <pasik@xxxxxx>
Date: Sat, 13 Mar 2010 00:30:35 +0200
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Fri, 12 Mar 2010 14:31:05 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4B9A24A1020000300008129C@xxxxxxxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <4B9A24A1020000300008129C@xxxxxxxxxxxxxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.18 (2008-05-17)
On Fri, Mar 12, 2010 at 11:25:21AM -0700, Ky Srinivasan wrote:
> The attached patch fixes some  bugs in usbfront.
> 

What kernel version is this patch against? linux-2.6.18-xen? 

-- Pasi

> Signed-off-by: K. Y. Srinivasan <ksrinivasan@xxxxxxxxxx>
> 
> 
> 
> 

> Bug#584218: Fix a  scheduling race in usbfront. Create the thread only after 
> we 
> are connected. The current code schedules the thread at a point where the 
> communication rings are not initialized yet.
> 
> Signed-off-by: K. Y. Srinivasan <ksrinivasan@xxxxxxxxxx>
> 
> Index: linux/drivers/xen/usbfront/xenbus.c
> ===================================================================
> --- linux.orig/drivers/xen/usbfront/xenbus.c  2010-03-10 12:10:58.000000000 
> -0700
> +++ linux/drivers/xen/usbfront/xenbus.c       2010-03-10 12:17:24.000000000 
> -0700
> @@ -192,11 +192,23 @@ static int connect(struct xenbus_device
>       usbif_conn_request_t *req;
>       int i, idx, err;
>       int notify;
> +     char name[TASK_COMM_LEN];
> +     struct usb_hcd *hcd;
> +
> +     hcd = info_to_hcd(info);
> +     snprintf(name, TASK_COMM_LEN, "xenhcd.%d", hcd->self.busnum);
>  
>       err = talk_to_backend(dev, info);
>       if (err)
>               return err;
>  
> +     info->kthread = kthread_run(xenhcd_schedule, info, name);
> +     if (IS_ERR(info->kthread)) {
> +             err = PTR_ERR(info->kthread);
> +             info->kthread = NULL;
> +             xenbus_dev_fatal(dev, err, "Error creating thread");
> +             return err;
> +     }
>       /* prepare ring for hotplug notification */
>       for (idx = 0, i = 0; i < USB_CONN_RING_SIZE; i++) {
>               req = RING_GET_REQUEST(&info->conn_ring, idx);
> @@ -274,7 +286,6 @@ static int usbfront_probe(struct xenbus_
>       int err;
>       struct usb_hcd *hcd;
>       struct usbfront_info *info;
> -     char name[TASK_COMM_LEN];
>  
>       if (usb_disabled())
>               return -ENODEV;
> @@ -298,13 +309,6 @@ static int usbfront_probe(struct xenbus_
>       }
>  
>       init_waitqueue_head(&info->wq);
> -     snprintf(name, TASK_COMM_LEN, "xenhcd.%d", hcd->self.busnum);
> -     info->kthread = kthread_run(xenhcd_schedule, info, name);
> -     if (IS_ERR(info->kthread)) {
> -             err = PTR_ERR(info->kthread);
> -             info->kthread = NULL;
> -             goto fail;
> -     }
>  
>       return 0;
>  
> @@ -343,8 +347,8 @@ static void backend_changed(struct xenbu
>       case XenbusStateInitWait:
>               if (dev->state != XenbusStateInitialising)
>                       break;
> -             connect(dev);
> -             xenbus_switch_state(dev, XenbusStateConnected);
> +             if (!connect(dev))
> +                     xenbus_switch_state(dev, XenbusStateConnected);
>               break;
>  
>       case XenbusStateClosing:

> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>