From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758783AbXJDItU (ORCPT ); Thu, 4 Oct 2007 04:49:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754254AbXJDItM (ORCPT ); Thu, 4 Oct 2007 04:49:12 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:44873 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753939AbXJDItL (ORCPT ); Thu, 4 Oct 2007 04:49:11 -0400 Date: Thu, 4 Oct 2007 01:48:28 -0700 From: Andrew Morton To: Jean Delvare Cc: LKML , Christoph Lameter , Roland Dreier Subject: Re: 2.6.23-rc8 build failure: __you_cannot_kmalloc_that_much in dmi_id_init Message-Id: <20071004014828.1bc971c8.akpm@linux-foundation.org> In-Reply-To: <20071002232642.568ea660@hyperion.delvare> References: <20071001225447.20f989aa@hyperion.delvare> <20071001235412.0737de78@hyperion.delvare> <20071002232642.568ea660@hyperion.delvare> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2 Oct 2007 23:26:42 +0200 Jean Delvare wrote: > On Mon, 1 Oct 2007 23:54:12 +0200, Jean Delvare wrote: > > On Mon, 1 Oct 2007 22:54:47 +0200, Jean Delvare wrote: > > > 2.6.23-rc8 and 2.6.23-rc8-git4 fail to build on one of my test > > > machines, with: > > > > > > drivers/built-in.o(.init.text+0x780e): In function `dmi_id_init': > > > : undefined reference to `__you_cannot_kmalloc_that_much' > > > > > > The code is allocating sizeof(struct device) so it really shouldn't be > > > a problem. I have no idea what's wrong. That's on i386, very old > > > machine (Pentium 166MMX / Intel TX chipset), with gcc 3.2.3 and > > > binutils 2.14.90.0.6. 2.6.22.9 compiles fine on the same system (but it > > > doesn't include dmi-id so it's not very surprising). > > > > > > .config attached. > > > > More information: building the same config on a much more recent system > > works fine. This seems to point at a toolchain issue. > > More information: > * No improvement in 2.6.23-rc9. > * Building the same config on a different system with the same > toolchain, fails the same. So it's not just one system acting weirdly, > the bug can be reproduced. > * I tried arbitrary values for the kzalloc() in dmi-id.c, the bottom line > is that anything above 64 bytes triggers the bug. > * The same kzalloc() in a different driver doesn't trigger the bug. > > I'm puzzled, no idea what to try next. > Yeah, the tricks we play in there do fool some versions of gcc, and you see the result. Roland came up with this: --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -145,7 +145,7 @@ static __always_inline struct kmem_cache *kmalloc_slab(size_t size) * testing it here shouldn't be needed. But some versions of gcc need * help. */ - if (__builtin_constant_p(size) && index < 0) { + if (__builtin_constant_p(index) && index < 0) { /* * Generate a link failure. Would be great if we could * do something to stop the compile here. Does it fix things for you?