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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 7A3F4C282DA for ; Tue, 16 Apr 2019 15:19:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 466D120872 for ; Tue, 16 Apr 2019 15:19:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728895AbfDPPTe (ORCPT ); Tue, 16 Apr 2019 11:19:34 -0400 Received: from mx2.suse.de ([195.135.220.15]:46340 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725796AbfDPPTe (ORCPT ); Tue, 16 Apr 2019 11:19:34 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 92646AE5D; Tue, 16 Apr 2019 15:19:32 +0000 (UTC) Subject: Re: [patch V5 01/32] mm/slab: Remove broken stack trace storage To: Thomas Gleixner Cc: Andy Lutomirski , Josh Poimboeuf , LKML , X86 ML , Sean Christopherson , Andrew Morton , Pekka Enberg , Linux-MM , David Rientjes References: <20190414155936.679808307@linutronix.de> <20190414160143.591255977@linutronix.de> <20190415132339.wiqyzygqklliyml7@treble> <20190415161657.2zwboghblj5ducux@treble> <612f9b99-a75b-6aeb-cf92-7dc5421cd950@suse.cz> From: Vlastimil Babka Openpgp: preference=signencrypt Autocrypt: addr=vbabka@suse.cz; prefer-encrypt=mutual; keydata= mQINBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 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xVKRSg3I2m+DUTVqBy7Lixo73hnW69kSjtqCeamY/NSu6LNP+b0wAOKhwz9hBEwEHLp05+mj 5ZFJyfGsOiNUcMoO/17FO4EBxSDP3FDLllpuzlFD7SXkfJaMWYmXIlO0jLzdfwfcnDzBbPwO hBM8hvtsyq8lq8vJOxv6XD6xcTtj5Az8t2JjdUX6SF9hxJpwhBU0wrCoGDkWp4Bbv6jnF7zP Nzftr4l8RuJoywDIiJpdaNpSlXKpj/K6KrnyAI/joYc7 Message-ID: <20effcc8-6d4d-bdd8-379e-8eed5624542c@suse.cz> Date: Tue, 16 Apr 2019 17:16:14 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/16/19 4:10 PM, Thomas Gleixner wrote: > kstack_end() is broken on interrupt stacks as they are not guaranteed to be > sized THREAD_SIZE and THREAD_SIZE aligned. > > As SLAB seems not to be used much with debugging enabled and might just go > away completely according to: > > https://lkml.kernel.org/r/612f9b99-a75b-6aeb-cf92-7dc5421cd950@suse.cz > > just remove the bogus code instead of trying to fix it. > > Fixes: 98eb235b7feb ("[PATCH] page unmapping debug") - History tree > Signed-off-by: Thomas Gleixner > Cc: Andrew Morton > Cc: Pekka Enberg > Cc: linux-mm@kvack.org Acked-by: Vlastimil Babka Thanks. > --- > V5: Remove the cruft. > V4: Make it actually work > V2: Made the code simpler to understand (Andy) > --- > mm/slab.c | 22 +++------------------- > 1 file changed, 3 insertions(+), 19 deletions(-) > > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -1470,33 +1470,17 @@ static bool is_debug_pagealloc_cache(str > static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr, > unsigned long caller) > { > - int size = cachep->object_size; > + int size = cachep->object_size / sizeof(unsigned long); > > addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)]; > > - if (size < 5 * sizeof(unsigned long)) > + if (size < 4) > return; > > *addr++ = 0x12345678; > *addr++ = caller; > *addr++ = smp_processor_id(); > - size -= 3 * sizeof(unsigned long); > - { > - unsigned long *sptr = &caller; > - unsigned long svalue; > - > - while (!kstack_end(sptr)) { > - svalue = *sptr++; > - if (kernel_text_address(svalue)) { > - *addr++ = svalue; > - size -= sizeof(unsigned long); > - if (size <= sizeof(unsigned long)) > - break; > - } > - } > - > - } > - *addr++ = 0x87654321; > + *addr = 0x87654321; > } > > static void slab_kernel_map(struct kmem_cache *cachep, void *objp, >