From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, T_DKIMWL_WL_HIGH,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22AB2C04AB5 for ; Thu, 6 Jun 2019 13:28:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E9CE020868 for ; Thu, 6 Jun 2019 13:28:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559827727; bh=UHWrtQgpvixRqPbEtkrChsh4DvWxscCBoV1YMgNBxGg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=2sQInZBB/cLlbMBtlSrg0bILaG4SAi0rJVMEK3iMvq/r3W5sYr9n36BIZWoZZR8ZQ 1dobqX9Q9wU05sbr1asvsjtek5ojf3N607S/1JeA0/EDFrjzohkCXbmoQRz3UZ2QIF iE4y09Qi9SIyl+WaZ/gy+j5vAdjn3hqVN5yzlp6M= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728128AbfFFN2q (ORCPT ); Thu, 6 Jun 2019 09:28:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:54996 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726014AbfFFN2p (ORCPT ); Thu, 6 Jun 2019 09:28:45 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A539D20866; Thu, 6 Jun 2019 13:28:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559827725; bh=UHWrtQgpvixRqPbEtkrChsh4DvWxscCBoV1YMgNBxGg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=0yjG6Bddq99LhfiaYiI3rJevdiHeIpzCUmVUfkqh052ofns7xizCLJEEC9QW8AWiR KwnSd5ZR1pPhnX7ZbkgIru9bVWnT57pk77L+901o8LE12SSIIYQfwZaXMVJHPetSEF qLNBBwl2a5cdhPnL08ZRoTAHkkoZZn9s0Ju27f2w= Date: Thu, 6 Jun 2019 15:28:42 +0200 From: Greg KH To: Dragan Cvetic Cc: arnd@arndb.de, michal.simek@xilinx.com, linux-arm-kernel@lists.infradead.org, robh+dt@kernel.org, mark.rutland@arm.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Derek Kiernan Subject: Re: [PATCH V4 04/12] misc: xilinx_sdfec: Add open, close and ioctl Message-ID: <20190606132842.GC7943@kroah.com> References: <1558784245-108751-1-git-send-email-dragan.cvetic@xilinx.com> <1558784245-108751-5-git-send-email-dragan.cvetic@xilinx.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1558784245-108751-5-git-send-email-dragan.cvetic@xilinx.com> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 25, 2019 at 12:37:17PM +0100, Dragan Cvetic wrote: > +static int xsdfec_dev_open(struct inode *iptr, struct file *fptr) > +{ > + return 0; > +} > + > +static int xsdfec_dev_release(struct inode *iptr, struct file *fptr) > +{ > + return 0; > +} empty open/close functions are never needed, just drop them. > + > +static long xsdfec_dev_ioctl(struct file *fptr, unsigned int cmd, > + unsigned long data) > +{ > + struct xsdfec_dev *xsdfec; > + void __user *arg = NULL; > + int rval = -EINVAL; > + > + xsdfec = container_of(fptr->private_data, struct xsdfec_dev, miscdev); > + if (!xsdfec) > + return rval; It is impossible for container_of() to return NULL, unless something very magical and rare just happened. It's just doing pointer math, you can never check the return value of it. > + > + if (_IOC_TYPE(cmd) != XSDFEC_MAGIC) > + return -ENOTTY; How can this happen? > + > + /* check if ioctl argument is present and valid */ > + if (_IOC_DIR(cmd) != _IOC_NONE) { > + arg = (void __user *)data; > + if (!arg) > + return rval; > + } > + > + switch (cmd) { > + default: > + /* Should not get here */ > + dev_warn(xsdfec->dev, "Undefined SDFEC IOCTL"); Nice that userspace has a way to fill up the kernel log :( Just return the correct error here, don't log it. thanks, greg k-h