Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754843AbbL3NtE (ORCPT ); Wed, 30 Dec 2015 08:49:04 -0500 Received: from mail-pa0-f52.google.com ([209.85.220.52]:36829 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753991AbbL3NtC (ORCPT ); Wed, 30 Dec 2015 08:49:02 -0500 Date: Wed, 30 Dec 2015 19:18:52 +0530 From: Sudip Mukherjee To: Bamvor Jian Zhang Cc: Arnd Bergmann , linux-kernel@vger.kernel.org, y2038@lists.linaro.org, gregkh@linuxfoundation.org, broonie@kernel.org Subject: Re: [PATCH v2 2/2] ppdev: add support for compat ioctl Message-ID: <20151230134852.GA21325@sudip-pc> References: <1450346332-31830-1-git-send-email-bamvor.zhangjian@linaro.org> <1450346332-31830-3-git-send-email-bamvor.zhangjian@linaro.org> <2687762.Ja01N3hBuT@wuerfel> <20151230111648.GA29697@sudip-pc> <5683DB05.7000704@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5683DB05.7000704@linaro.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2571 Lines: 72 On Wed, Dec 30, 2015 at 09:24:21PM +0800, Bamvor Jian Zhang wrote: > Hi, Sudip > > On 12/30/2015 07:16 PM, Sudip Mukherjee wrote: > > On Fri, Dec 18, 2015 at 12:12:05AM +0100, Arnd Bergmann wrote: > >> On Thursday 17 December 2015 17:58:52 Bamvor Jian Zhang wrote: > >>> The arg of ioctl in ppdev is the pointer of integer except the > >>> timeval in PPSETTIME, PPGETTIME. Different size of timeval > >>> is already supported by the previous patches. So, it is safe > >>> to add compat support. > >>> > >>> Signed-off-by: Bamvor Jian Zhang > >>> > >> > >> Reviewed-by: Arnd Bergmann > >> > >> (I think I replied with the reviewed-by tag before to this patch) > > > > I was testing this series today. And it is breaking my userspace code. I > > am attaching my userspace code for you to check. Its very simple > > userspace code: > > 1: open > > 2: ioctl to claim > > 3: ioctl - PPGETTIME > > 4: ioctl - PPSETTIME > > 5: ioctl - PPGETTIME > > 6: ioctl - release > > 7: close > > > > Without this series it works as expected. > > > > With this series applied, the userspace code prints the error message: > > PPNEGOT: Bad address > > > > I traced it with strace and: > > ioctl(3, PPGETTIME, 0xbfe91508) = -1 EFAULT (Bad address) > Thanks for your testing. It seems that I misuse the parameters. Could > you please apply the following patch and try it again? > There is no parport in my computer, Thanks. > > diff --git a/drivers/char/ppdev.c b/drivers/char/ppdev.c > index 31bc7b7..9e98d01 100644 > --- a/drivers/char/ppdev.c > +++ b/drivers/char/ppdev.c > @@ -636,7 +636,7 @@ static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > if ((time32[0] < 0) || (time32[1] < 0)) > return -EINVAL; > > - if (copy_to_user(time32, argp, sizeof(time32))) > + if (copy_to_user(argp, time32, sizeof(time32))) > return -EFAULT; > > return 0; > @@ -648,7 +648,7 @@ static int pp_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg) > if ((time64[0] < 0) || (time64[1] < 0)) > return -EINVAL; > > - if (copy_to_user(time64, argp, sizeof(time64))) > + if (copy_to_user(argp, time64, sizeof(time64))) > return -EFAULT; > > return 0; It works. Tomorrow I will test it on a 64 bit system also. regards sudip -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/