Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933569Ab3D3R15 (ORCPT ); Tue, 30 Apr 2013 13:27:57 -0400 Received: from a9-62.smtp-out.amazonses.com ([54.240.9.62]:38869 "EHLO a9-62.smtp-out.amazonses.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932772Ab3D3R1z (ORCPT ); Tue, 30 Apr 2013 13:27:55 -0400 Date: Tue, 30 Apr 2013 17:27:53 +0000 From: Christoph Lameter X-X-Sender: cl@gentwo.org To: Tetsuo Handa cc: glommer@parallels.com, penberg@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [linux-next-20130422] Bug in SLAB? In-Reply-To: <201305010101.CGB86424.JFQOtSFOVOLFHM@I-love.SAKURA.ne.jp> Message-ID: <0000013e5bfc7c4d-54fa9464-dccd-4157-b4a5-22594261eaf3-000000@email.amazonses.com> References: <0000013e564e0e5a-121c52f9-e489-470f-99d5-67a5ad42eb75-000000@email.amazonses.com> <201304300028.IAD13051.OHOVMJSLFFFQOt@I-love.SAKURA.ne.jp> <0000013e56e9304a-1042a95a-d4dd-43c5-8b8a-c670f50ac54e-000000@email.amazonses.com> <201304300645.FCE37285.tVHJLSOMQFOFFO@I-love.SAKURA.ne.jp> <0000013e5b56d067-7982dfa6-08a2-4c48-ad77-6888b5114c5f-000000@email.amazonses.com> <201305010101.CGB86424.JFQOtSFOVOLFHM@I-love.SAKURA.ne.jp> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-SES-Outgoing: 2013.04.30-54.240.9.62 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1534 Lines: 39 On Wed, 1 May 2013, Tetsuo Handa wrote: > Christoph Lameter wrote: > > On Tue, 30 Apr 2013, Tetsuo Handa wrote: > > > > > The testcases still trigger BUG() at 32M: > > > > I thought we established that MAX_ORDER only allows a maximum of 8M sized > > allocations? Why are you trying 32M? > > Only for regression testing. At least until Linux 3.9, requesting too large > size didn't trigger oops, did it? I'm not expecting kmalloc() to trigger oops > for Linux 3.10 and future kernels. It did for SLUB. SLAB returned NULL for some cases. > "kmalloc() returning NULL for these allocations" is needed by "try kmalloc() > first, fallback to vmalloc()" allocation. There are kernel modules which expect > kmalloc() to return NULL rather than oops when the requested size is larger > than KMALLOC_MAX_SIZE bytes. If kmalloc() suddenly starts triggering oops, such > modules will break. This behavior has been in there for years. Why try a kmalloc that always fails since the size is too big? > Anyway, there is a regression we want to fix : we won't be able to boot > Linux 3.10-rc1 for x86_32 built with CONFIG_DEBUG_SLAB=y && > CONFIG_DEBUG_SPINLOCK=y && CONFIG_DEBUG_PAGEALLOC=y . > ("Fix off by one error in slab.h" did not fix the regression.) Hmm... Where does this fail? In slab? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/