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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 5CB42C433E0 for ; Tue, 9 Mar 2021 18:13:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CE88F6518F for ; Tue, 9 Mar 2021 18:13:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CE88F6518F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4F8438D012E; Tue, 9 Mar 2021 13:13:04 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4A5F78D012A; Tue, 9 Mar 2021 13:13:04 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2F92F8D012E; Tue, 9 Mar 2021 13:13:04 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0236.hostedemail.com [216.40.44.236]) by kanga.kvack.org (Postfix) with ESMTP id 0FAF78D012A for ; Tue, 9 Mar 2021 13:13:04 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id B7D2A824999B for ; Tue, 9 Mar 2021 18:13:03 +0000 (UTC) X-FDA: 77901132246.22.499C857 Received: from mail-wr1-f47.google.com (mail-wr1-f47.google.com [209.85.221.47]) by imf30.hostedemail.com (Postfix) with ESMTP id EC347E007A7B for ; Tue, 9 Mar 2021 18:12:51 +0000 (UTC) Received: by mail-wr1-f47.google.com with SMTP id u14so17563655wri.3 for ; Tue, 09 Mar 2021 10:12:57 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=to:cc:references:from:subject:message-id:date:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=PnYU7rXIm7fcsv/hTsu+HY5l1Jj4HcmP4vRljn+UL84=; b=qR5tP57vrensSHbH0zTfCAQMKlFwNJ6pXRCQSZDrkzncBoB28xokLS6QVZpiNe4fr8 0pgpNd7zndmhW2ig/6gn3RYJDIPLp0lS13rct6+gU0k0oX0TwjRCPdWzMpmLJeWIthLT S52RwHOBw8SVnPDE9hqdwwxdVnMBSQsi5VOYDRn/zJ7NgiEH9fzW9FRpDUqymnXimQu8 U3g3he3LMEuR6H/zt9E7SuqfW/c8bUbI1DQVnOtepv9cxGvRGOschdkK/zQ/D2ire11O GztfqC1JM4kw5YYgbCAWJsBJdLGPcAj0+jJV9AACiphEkkSCy0unKbwaACHRFCgJK43P s3Jg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:references:from:subject:message-id:date :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=PnYU7rXIm7fcsv/hTsu+HY5l1Jj4HcmP4vRljn+UL84=; b=Ay6UIfEJwpQdH7sFa7FzRNl7Kqez/KOJWn8sKe1yPjG0S6trth2vbFa23w7fZ/azxC EYZlXdtLbvbMa/C9LVs3gN1evxr3WNMPzeQx+p3W4Vl/wOPDSeohqEOxTio1QrmQk77Z N41blxycLhdAMFvT2gpaugkczeKMOTEWfnv5cPJPC+o2y9tzK66VOIcmH9l3/4G7AsXP XE9+MUtFNVq/GYE+4yslgOQ614dSRluvbqtxm4exvcalZjayS8FlsM7IGU6DpwjFVRTw E29Qt9Hcw2jy3wW8p9A7aUAWDNwX6sb+ew9mUBUPWxVaNztzsJoKNOzmgvtHZF715gRI ihKw== X-Gm-Message-State: AOAM531FwsGbe0at5wvMA4JkgTFULI8QAzKmzT07ZA1eOhzB7F6YYrg8 HebzREcJr7vTfKIRUHkmWWfERA== X-Google-Smtp-Source: ABdhPJyUhmCZRb3yVzm1lSCDABma40ZstGQI5xbIv0evvrzQxGSMPzx3lANEC5guKWGQV3XPb95Otw== X-Received: by 2002:a5d:4fc5:: with SMTP id h5mr30693815wrw.33.1615313576019; Tue, 09 Mar 2021 10:12:56 -0800 (PST) Received: from [10.44.66.8] ([212.45.67.2]) by smtp.googlemail.com with ESMTPSA id n186sm5189504wmn.22.2021.03.09.10.12.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 09 Mar 2021 10:12:55 -0800 (PST) To: Christoph Lameter 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 References: <20210309134720.29052-1-georgi.djakov@linaro.org> From: Georgi Djakov Subject: Re: [PATCH] mm/slub: Add slub_debug option to panic on memory corruption Message-ID: Date: Tue, 9 Mar 2021 20:12:53 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Stat-Signature: yd4x6dpe978ekh6a6xf5dhja6oiah7zn X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: EC347E007A7B Received-SPF: none (linaro.org>: No applicable sender policy available) receiver=imf30; identity=mailfrom; envelope-from=""; helo=mail-wr1-f47.google.com; client-ip=209.85.221.47 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615313571-362855 Content-Transfer-Encoding: quoted-printable 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: Hi Christoph, Thanks for the comments! On 3/9/21 16:56, Christoph Lameter wrote: > On Tue, 9 Mar 2021, Georgi Djakov wrote: >=20 >> 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. >=20 > Hmmm.... ok. The idea is to be able to collect data right after the corruption is detected, otherwise more data might be corrupted and tracing becomes more difficult. >=20 >> static void restore_bytes(struct kmem_cache *s, char *message, u8 da= ta, >> void *from, void *to) >> { >> + if (slub_debug & SLAB_CORRUPTION_PANIC) >> + panic("slab: object overwritten\n"); >> slab_fix(s, "Restoring 0x%p-0x%p=3D0x%x\n", from, to - 1, data); >> memset(from, data, to - from); >> } >=20 > Why panic here? This should only be called late in the bug reporting wh= en > an error has already been printed. This is called by both slab_pad_check() and check_bytes_and_report(), so = it seemed like a common place where i could put the panic(). I can move it t= o the caller functions instead, if that's preferred. Thanks, Georgi