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Date: Wed, 21 Sep 2016 18:48:09 +0200
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Subject: Re: [Qemu-devel] [PATCH for v2.6.0] net: imx: check buffer
 descriptor length
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To: P J P <ppandit@redhat.com>, Qemu Developers <qemu-devel@nongnu.org>
Cc: Jason Wang <jasowang@redhat.com>, Li Qiang <liqiang6-s@360.cn>, Prasad J Pandit <pjp@fedoraproject.org>



On 21/09/2016 15:45, P J P wrote:
> From: Prasad J Pandit <pjp@fedoraproject.org>
> 
> i.MX Fast Ethernet Controller uses buffer descriptors to manage
> data flow to/fro receive & transmit queues. While transmitting
> packets, it could continue to read buffer descriptors if a buffer
> descriptor has length of zero. Add check to avoid it.
> 
> Reported-by: Li Qiang <liqiang6-s@360.cn>
> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
> ---
>  hw/net/imx_fec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/net/imx_fec.c b/hw/net/imx_fec.c
> index e60e338..31870b0 100644
> --- a/hw/net/imx_fec.c
> +++ b/hw/net/imx_fec.c
> @@ -276,7 +276,7 @@ static void imx_fec_do_tx(IMXFECState *s)
>          imx_fec_read_bd(&bd, addr);
>          FEC_PRINTF("tx_bd %x flags %04x len %d data %08x\n",
>                     addr, bd.flags, bd.length, bd.data);
> -        if ((bd.flags & FEC_BD_R) == 0) {
> +        if (!bd.length || (bd.flags & FEC_BD_R) == 0) {
>              /* Run out of descriptors to transmit.  */
>              break;
>          }
> 

Same here---and same bug as the previous patch too:

diff --git a/hw/net/imx_fec.c b/hw/net/imx_fec.c
index 1c415ab..50c7564 100644
--- a/hw/net/imx_fec.c
+++ b/hw/net/imx_fec.c
@@ -429,7 +429,7 @@ static void imx_fec_do_tx(IMXFECState *s)
         frame_size += len;
         if (bd.flags & ENET_BD_L) {
             /* Last buffer in frame.  */
-            qemu_send_packet(qemu_get_queue(s->nic), frame, len);
+            qemu_send_packet(qemu_get_queue(s->nic), frame, frame_size);
             ptr = frame;
             frame_size = 0;
             s->regs[ENET_EIR] |= ENET_INT_TXF;

Paolo