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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 05885C2D0A3 for ; Wed, 4 Nov 2020 02:30:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B6EB1216C4 for ; Wed, 4 Nov 2020 02:30:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604457014; bh=2ZfJqIORjLB7q6zIRwiMeO00SRx9XOpoB4zxqcAStZQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=AIRGQhnAa5vjZRXEBqpUrje92mtEXmol0ATUhBsNdZ0djA9KeZwms/DuoquAjtVhe QSwl1oKzkEg+mVcMcsmAQ9RA9kB2ObjteP429wxPTXpo0ng0baoOUQWFl6jiOyf09o rTq3QromaM2GELJn5HyqNtluE+GnZ8fd90VBZoOc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730211AbgKDC3K (ORCPT ); Tue, 3 Nov 2020 21:29:10 -0500 Received: from mail.kernel.org ([198.145.29.99]:34600 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729188AbgKDC3K (ORCPT ); Tue, 3 Nov 2020 21:29:10 -0500 Received: from sol.localdomain (172-10-235-113.lightspeed.sntcca.sbcglobal.net [172.10.235.113]) (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 D861C216C4; Wed, 4 Nov 2020 02:29:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604456950; bh=2ZfJqIORjLB7q6zIRwiMeO00SRx9XOpoB4zxqcAStZQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JUbc06gcfBLn8oELert5Splrgauetjeyxyh9ubPz1PBQ2Bjm7XHR0I2uod6IRs2XE i/dA/HaJqxwKJ+pcRpLYr+7KSW6WopibJ5K3yrQBVW2cAjWnHU2QL2hx/+b6brHtMv YHVYFNlOTWVA7DSDUjnGQ7mltm/2DrNMsC/paekY= Date: Tue, 3 Nov 2020 18:29:08 -0800 From: Eric Biggers To: Chao Yu Cc: jaegeuk@kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH RFC] f2fs: fix compat F2FS_IOC_{MOVE, GARBAGE_COLLECT}_RANGE Message-ID: <20201104022908.GA832@sol.localdomain> References: <20201104021906.108534-1-yuchao0@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201104021906.108534-1-yuchao0@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 04, 2020 at 10:19:06AM +0800, Chao Yu wrote: > Eric reported a ioctl bug in below link: > > https://lore.kernel.org/linux-f2fs-devel/20201103032234.GB2875@sol.localdomain/ > > That said, on some 32-bit architectures, u64 has only 32-bit alignment, > notably i386 and x86_32, so that size of struct f2fs_gc_range compiled > in x86_32 is 20 bytes, however the size in x86_64 is 24 bytes, binary > compiled in x86_32 can not call F2FS_IOC_GARBAGE_COLLECT_RANGE successfully > due to mismatched value of ioctl command in betweeen binary and f2fs > module, similarly, F2FS_IOC_MOVE_RANGE will fail too. > > In this patch we introduce two ioctls for compatibility of above special > 32-bit binary: > - F2FS_IOC32_GARBAGE_COLLECT_RANGE > - F2FS_IOC32_MOVE_RANGE > > Signed-off-by: Chao Yu > --- > > Jaegeuk, Eric, > > I have no 32-bit machine now, so I don't run any test on this patch, > please take a look at this RFC patch first. You can test this by running a 32-bit binary on a machine with a 64-bit kernel. E.g. on x86_64, compile a binary with 'gcc -m32'. > #ifdef CONFIG_COMPAT > +static int f2fs_compat_ioc_gc_range(struct file *file, unsigned long arg) > +{ > + struct compat_f2fs_gc_range __user *urange; > + struct f2fs_gc_range range; > + int err; > + > + urange = compat_ptr(arg); > + err = get_user(range.sync, &urange->sync); > + err |= get_user(range.start, &urange->start); > + err |= get_user(range.len, &urange->len); > + if (err) > + return -EFAULT; > + if (unlikely(f2fs_cp_error(F2FS_I_SB(file_inode(file))))) > + return -EIO; > + if (!f2fs_is_checkpoint_ready(F2FS_I_SB(file_inode(file)))) > + return -ENOSPC; > + return f2fs_ioc_gc_range(file, (unsigned long)&range); > +} This won't work because f2fs_ioc_gc_range() expects a user pointer. You'll need to make the native and compat versions do the copy from user separately, and have them call a helper function that takes a pointer to the argument in kernel memory. - Eric