From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH net,stable-4.0] cdc_ncm: Fix tx_bytes statistics Date: Fri, 22 May 2015 18:22:47 +0100 Message-ID: <1432315367.22824.19.camel@codethink.co.uk> References: <1432293322-11928-1-git-send-email-bjorn@mork.no> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org, Florian Bruhin , linux-usb@vger.kernel.org, Oliver Neukum To: =?ISO-8859-1?Q?Bj=F8rn?= Mork Return-path: Received: from ducie-dc1.codethink.co.uk ([185.25.241.215]:38332 "EHLO ducie-dc1.codethink.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757541AbbEVRWx (ORCPT ); Fri, 22 May 2015 13:22:53 -0400 In-Reply-To: <1432293322-11928-1-git-send-email-bjorn@mork.no> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, 2015-05-22 at 13:15 +0200, Bj=C3=B8rn Mork wrote: > The tx_curr_frame_payload field is u32. When we try to calculate a > small negative delta based on it, we end up with a positive integer > close to 2^32 instead. So the tx_bytes pointer increases by about > 2^32 for every transmitted frame. >=20 > Fix by calculating the delta as a signed long. Told you I hadn't tested it. Ben. > Cc: Ben Hutchings > Reported-by: Florian Bruhin > Fixes: 7a1e890e2168 ("usbnet: Fix tx_bytes statistic running backward= in cdc_ncm") > Signed-off-by: Bj=C3=B8rn Mork > --- > drivers/net/usb/cdc_ncm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) >=20 > diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c > index c3e4da9e79ca..8067b8fbb0ee 100644 > --- a/drivers/net/usb/cdc_ncm.c > +++ b/drivers/net/usb/cdc_ncm.c > @@ -1182,7 +1182,7 @@ cdc_ncm_fill_tx_frame(struct usbnet *dev, struc= t sk_buff *skb, __le32 sign) > * payload data instead. > */ > usbnet_set_skb_tx_stats(skb_out, n, > - ctx->tx_curr_frame_payload - skb_out->len); > + (long)ctx->tx_curr_frame_payload - skb_out->len); > =20 > return skb_out; > =20