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Date: Wed, 31 Jul 2013 14:26:55 +0200
From: Laszlo Ersek <lersek@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] xhci: fix segfault
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To: Gerd Hoffmann <kraxel@redhat.com>
Cc: qemu-devel@nongnu.org, qemu-stable@nongnu.org

On 07/31/13 11:10, Gerd Hoffmann wrote:
> Guest trying to reset a endpoint of a disconnected device resulted in
> xhci trying to dereference uport while being NULL, thereby crashing
> qemu.  Fix that by adding a check.  Drop unused dev variable while
> touching that code bit.
> 
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  hw/usb/hcd-xhci.c |    5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
> index a4cb13a..a922cb4 100644
> --- a/hw/usb/hcd-xhci.c
> +++ b/hw/usb/hcd-xhci.c
> @@ -1443,7 +1443,6 @@ static TRBCCode xhci_reset_ep(XHCIState *xhci, unsigned int slotid,
>  {
>      XHCISlot *slot;
>      XHCIEPContext *epctx;
> -    USBDevice *dev;
>  
>      trace_usb_xhci_ep_reset(slotid, epid);
>      assert(slotid >= 1 && slotid <= xhci->numslots);
> @@ -1479,8 +1478,8 @@ static TRBCCode xhci_reset_ep(XHCIState *xhci, unsigned int slotid,
>          ep |= 0x80;
>      }
>  
> -    dev = xhci->slots[slotid-1].uport->dev;
> -    if (!dev) {
> +    if (!xhci->slots[slotid-1].uport ||
> +        !xhci->slots[slotid-1].uport->dev) {
>          return CC_USB_TRANSACTION_ERROR;
>      }
>  
> 

Reviewed-by: Laszlo Ersek <lersek@redhat.com>