From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:39466 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752003AbcE1KLF (ORCPT ); Sat, 28 May 2016 06:11:05 -0400 Subject: Re: ascot2e.c off by one bug To: Saso Slavicic , linux-media@vger.kernel.org References: <000f01d1b8c3$54af4080$fe0dc180$@astim.si> From: Antti Palosaari Message-ID: <424b5c9e-2019-76cc-5f2e-e68e43cfd6f8@iki.fi> Date: Sat, 28 May 2016 13:11:02 +0300 MIME-Version: 1.0 In-Reply-To: <000f01d1b8c3$54af4080$fe0dc180$@astim.si> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Convert it to regmap at the same (just a hint...) On 05/28/2016 12:28 PM, Saso Slavicic wrote: > Hi, > > Tuning a card with Sony ASCOT2E produces the following error: > > kernel: i2c i2c-9: wr reg=0006: len=11 is too big! > > MAX_WRITE_REGSIZE is defined as 10, buf[MAX_WRITE_REGSIZE + 1] buffer is > used in ascot2e_write_regs(). > > The problem is that exactly 10 bytes are written in ascot2e_set_params(): > > /* Set BW_OFFSET (0x0F) value from parameter table */ > data[9] = ascot2e_sett[tv_system].bw_offset; > ascot2e_write_regs(priv, 0x06, data, 10); > > The test in write_regs is as follows: > > if (len + 1 >= sizeof(buf)) > > 10 + 1 = 11 and that would be exactly the size of buf. Since 10 bytes + > buf[0] = reg would seem to fit into buf[], this shouldn't be an error. > > The following patch fixes the problem for me, I have tested the card and it > seems to be working fine. > > --- > drivers/media/dvb-frontends/ascot2e.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/drivers/media/dvb-frontends/ascot2e.c > b/drivers/media/dvb-frontends/ascot2e.c > --- a/drivers/media/dvb-frontends/ascot2e.c > +++ b/drivers/media/dvb-frontends/ascot2e.c > @@ -132,7 +132,7 @@ static int ascot2e_write_regs(struct ascot2e_priv *priv, > } > }; > > - if (len + 1 >= sizeof(buf)) { > + if (len + 1 > sizeof(buf)) { > dev_warn(&priv->i2c->dev,"wr reg=%04x: len=%d is too > big!\n", > reg, len + 1); > return -E2BIG; > > Regards, > Saso Slavicic > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-media" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- http://palosaari.fi/