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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 AE89CC433DB for ; Tue, 9 Mar 2021 15:06:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7A89965259 for ; Tue, 9 Mar 2021 15:06:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231753AbhCIPGB (ORCPT ); Tue, 9 Mar 2021 10:06:01 -0500 Received: from vmi485042.contaboserver.net ([161.97.139.209]:54778 "EHLO gentwo.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231660AbhCIPFs (ORCPT ); Tue, 9 Mar 2021 10:05:48 -0500 Received: by gentwo.de (Postfix, from userid 1001) id C06D0B00BAC; Tue, 9 Mar 2021 15:56:04 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by gentwo.de (Postfix) with ESMTP id BF87DB0096F; Tue, 9 Mar 2021 15:56:04 +0100 (CET) Date: Tue, 9 Mar 2021 15:56:04 +0100 (CET) From: Christoph Lameter To: Georgi Djakov cc: linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, corbet@lwn.net, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/slub: Add slub_debug option to panic on memory corruption In-Reply-To: <20210309134720.29052-1-georgi.djakov@linaro.org> Message-ID: References: <20210309134720.29052-1-georgi.djakov@linaro.org> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 9 Mar 2021, Georgi Djakov wrote: > Being able to stop the system immediately when a memory corruption > is detected is crucial to finding the source of it. This is very > useful when the memory can be inspected with kdump or other tools. Hmmm.... ok. > static void restore_bytes(struct kmem_cache *s, char *message, u8 data, > void *from, void *to) > { > + if (slub_debug & SLAB_CORRUPTION_PANIC) > + panic("slab: object overwritten\n"); > slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data); > memset(from, data, to - from); > } Why panic here? This should only be called late in the bug reporting when an error has already been printed. 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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 3A045C433E0 for ; Tue, 9 Mar 2021 14:56:35 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1EF456524C for ; Tue, 9 Mar 2021 14:56:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1EF456524C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gentwo.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5A0448D00F8; Tue, 9 Mar 2021 09:56:33 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 54FCE8D007F; Tue, 9 Mar 2021 09:56:33 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3F0888D00F8; Tue, 9 Mar 2021 09:56:33 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0106.hostedemail.com [216.40.44.106]) by kanga.kvack.org (Postfix) with ESMTP id 21A8B8D007F for ; Tue, 9 Mar 2021 09:56:33 -0500 (EST) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id D1839180AD81D for ; Tue, 9 Mar 2021 14:56:32 +0000 (UTC) X-FDA: 77900637024.27.2ABF450 Received: from gentwo.de (vmi485042.contaboserver.net [161.97.139.209]) by imf17.hostedemail.com (Postfix) with ESMTP id 416CC407F8DB for ; Tue, 9 Mar 2021 14:56:31 +0000 (UTC) Received: by gentwo.de (Postfix, from userid 1001) id C06D0B00BAC; Tue, 9 Mar 2021 15:56:04 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by gentwo.de (Postfix) with ESMTP id BF87DB0096F; Tue, 9 Mar 2021 15:56:04 +0100 (CET) Date: Tue, 9 Mar 2021 15:56:04 +0100 (CET) From: Christoph Lameter To: Georgi Djakov cc: linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, corbet@lwn.net, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/slub: Add slub_debug option to panic on memory corruption In-Reply-To: <20210309134720.29052-1-georgi.djakov@linaro.org> Message-ID: References: <20210309134720.29052-1-georgi.djakov@linaro.org> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Stat-Signature: fgiqnc5ffcgdkrd5b5kbbunpknd9um76 X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 416CC407F8DB Received-SPF: none (gentwo.de>: No applicable sender policy available) receiver=imf17; identity=mailfrom; envelope-from=""; helo=gentwo.de; client-ip=161.97.139.209 X-HE-DKIM-Result: none/none X-HE-Tag: 1615301791-137090 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 9 Mar 2021, Georgi Djakov wrote: > Being able to stop the system immediately when a memory corruption > is detected is crucial to finding the source of it. This is very > useful when the memory can be inspected with kdump or other tools. Hmmm.... ok. > static void restore_bytes(struct kmem_cache *s, char *message, u8 data, > void *from, void *to) > { > + if (slub_debug & SLAB_CORRUPTION_PANIC) > + panic("slab: object overwritten\n"); > slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data); > memset(from, data, to - from); > } Why panic here? This should only be called late in the bug reporting when an error has already been printed.