From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx01.sz.bfs.de ([194.94.69.103]:51784 "EHLO mx01.sz.bfs.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932247Ab2ARRQy (ORCPT ); Wed, 18 Jan 2012 12:16:54 -0500 Message-ID: <4F16FC26.80306@bfs.de> Date: Wed, 18 Jan 2012 18:06:46 +0100 From: walter harms Reply-To: wharms@bfs.de MIME-Version: 1.0 To: Dan Carpenter CC: Mauro Carvalho Chehab , "Igor M. Liplianin" , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [patch 2/2] [media] ds3000: off by one in ds3000_read_snr() References: <20120117073021.GB11358@elgon.mountain> In-Reply-To: <20120117073021.GB11358@elgon.mountain> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Am 17.01.2012 08:30, schrieb Dan Carpenter: > This is a static checker patch and I don't have the hardware to test > this, so please review it carefully. The dvbs2_snr_tab[] array has 80 > elements so when we cap it at 80, that's off by one. I would have > assumed that the test was wrong but in the lines right before we have > the same test but use "snr_reading - 1" as the array offset. I've done > the same thing here. > > Signed-off-by: Dan Carpenter > > diff --git a/drivers/media/dvb/frontends/ds3000.c b/drivers/media/dvb/frontends/ds3000.c > index af65d01..3f5ae0a 100644 > --- a/drivers/media/dvb/frontends/ds3000.c > +++ b/drivers/media/dvb/frontends/ds3000.c > @@ -681,7 +681,7 @@ static int ds3000_read_snr(struct dvb_frontend *fe, u16 *snr) > snr_reading = dvbs2_noise_reading / tmp; > if (snr_reading > 80) > snr_reading = 80; > - *snr = -(dvbs2_snr_tab[snr_reading] / 1000); > + *snr = -(dvbs2_snr_tab[snr_reading - 1] / 1000); > } > dprintk("%s: raw / cooked = 0x%02x / 0x%04x\n", __func__, > snr_reading, *snr); hi dan, perhaps it is more useful to do it in the check above ? thinking about that why not replace the number (80) with ARRAY_SIZE() ? re, wh