diff mbox series

usb/storage: clear csw on reset

Message ID 20210312094954.796799-1-kraxel@redhat.com (mailing list archive)
State New, archived
Headers show
Series usb/storage: clear csw on reset | expand

Commit Message

Gerd Hoffmann March 12, 2021, 9:49 a.m. UTC 
Stale data in csw (specifically residue) can confuse the state machine
and allows the guest trigger an assert().  So clear csw on reset to
avoid this happening in case the guest resets the device in the middle
of a request.

Buglink: https://bugs.launchpad.net/qemu/+bug/1523811
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 hw/usb/dev-storage.c | 1 +
 1 file changed, 1 insertion(+)

Comments

Philippe Mathieu-Daudé March 12, 2021, 10:01 a.m. UTC | #1 
On 3/12/21 10:49 AM, Gerd Hoffmann wrote:
> Stale data in csw (specifically residue) can confuse the state machine
> and allows the guest trigger an assert().  So clear csw on reset to
> avoid this happening in case the guest resets the device in the middle
> of a request.
> 
> Buglink: https://bugs.launchpad.net/qemu/+bug/1523811
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  hw/usb/dev-storage.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/hw/usb/dev-storage.c b/hw/usb/dev-storage.c
> index a5f76fc00120..fd4ea818115c 100644
> --- a/hw/usb/dev-storage.c
> +++ b/hw/usb/dev-storage.c
> @@ -352,6 +352,7 @@ static void usb_msd_handle_reset(USBDevice *dev)
>          usb_msd_packet_complete(s);
>      }
>  
> +    memset(&s->csw, 0, sizeof(s->csw));

easy-peasy...

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

>      s->mode = USB_MSDM_CBW;
>  }
diff mbox series

Patch

diff --git a/hw/usb/dev-storage.c b/hw/usb/dev-storage.c
index a5f76fc00120..fd4ea818115c 100644
--- a/hw/usb/dev-storage.c
+++ b/hw/usb/dev-storage.c
@@ -352,6 +352,7 @@  static void usb_msd_handle_reset(USBDevice *dev)
         usb_msd_packet_complete(s);
     }
 
+    memset(&s->csw, 0, sizeof(s->csw));
     s->mode = USB_MSDM_CBW;
 }