From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH 1/2] i2c-dev: don't get i2c adapter via i2c_dev Date: Thu, 7 Jul 2016 15:16:54 +0200 Message-ID: <20160707151654.3d32741c@endymion> References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.suse.de ([195.135.220.15]:35376 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750879AbcGGNRD (ORCPT ); Thu, 7 Jul 2016 09:17:03 -0400 In-Reply-To: Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: Viresh Kumar Cc: Wolfram Sang , Jean Delvare , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, Johan Hovold , Alex Elder On Tue, 5 Jul 2016 19:57:06 -0700, Viresh Kumar wrote: > There is no code protecting i2c_dev to be freed after it is returned > from i2c_dev_get_by_minor() and using it to access the value which we > already have (minor) isn't safe really. > > Avoid using it and get the adapter directly from 'minor'. > > Signed-off-by: Viresh Kumar > --- > drivers/i2c/i2c-dev.c | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) > > diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c > index 6ecfd76270f2..66f323fd3982 100644 > --- a/drivers/i2c/i2c-dev.c > +++ b/drivers/i2c/i2c-dev.c > @@ -485,13 +485,8 @@ static int i2cdev_open(struct inode *inode, struct file *file) > unsigned int minor = iminor(inode); > struct i2c_client *client; > struct i2c_adapter *adap; > - struct i2c_dev *i2c_dev; > - > - i2c_dev = i2c_dev_get_by_minor(minor); > - if (!i2c_dev) > - return -ENODEV; > > - adap = i2c_get_adapter(i2c_dev->adap->nr); > + adap = i2c_get_adapter(minor); > if (!adap) > return -ENODEV; > Anyway, this is a good cleanup/optimization on its own, on top of fixing a race condition, independently of what we decide for the rest of the problems being discussed in this thread. So: Reviewed-by: Jean Delvare Tested-by: Jean Delvare Thanks, -- Jean Delvare SUSE L3 Support