From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: linux-next: build failure after merge of the aio tree Date: Thu, 4 Feb 2016 16:17:42 +0000 Message-ID: <20160204161741.GH10826@n2100.arm.linux.org.uk> References: <20160129113056.GP10826@n2100.arm.linux.org.uk> <20160204131959.6695c7bf@canb.auug.org.au> <20160204134142.GA16315@kvack.org> <20160204135056.GE10826@n2100.arm.linux.org.uk> <20160204140822.GB16315@kvack.org> <20160204141253.GF10826@n2100.arm.linux.org.uk> <20160204143204.GC16315@kvack.org> <20160204143907.GG10826@n2100.arm.linux.org.uk> <20160204160101.GD16315@kvack.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from pandora.arm.linux.org.uk ([78.32.30.218]:58307 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932330AbcBDQRy (ORCPT ); Thu, 4 Feb 2016 11:17:54 -0500 Content-Disposition: inline In-Reply-To: <20160204160101.GD16315@kvack.org> Sender: linux-next-owner@vger.kernel.org List-ID: To: Benjamin LaHaise Cc: Stephen Rothwell , Geert Uytterhoeven , Linux-Next , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" On Thu, Feb 04, 2016 at 11:01:01AM -0500, Benjamin LaHaise wrote: > On Thu, Feb 04, 2016 at 02:39:07PM +0000, Russell King - ARM Linux wrote: > > However, this one should warn: > > > > int test_wrong(char **v, const char **p) > > { return __get_user(*v, p); } > > > > Good luck (I think you'll need lots of it to get a working solution)! :) > > This works with your test cases on x86-32. Note that it's only compile + > link tested at present. That's the easy bit! The problem you're going to run into is here: #define __get_user_nocheck(x, ptr, size) \ ({ \ int __gu_err; \ unsigned long __gu_val; \ __uaccess_begin(); \ __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ __uaccess_end(); \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ __gu_val will be 32-bit, even when you're wanting a 64-bit quantity. That's where the fun and games start... -- RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.