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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 EF348C433DB for ; Thu, 11 Mar 2021 21:38:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF9A464F19 for ; Thu, 11 Mar 2021 21:38:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231238AbhCKViN (ORCPT ); Thu, 11 Mar 2021 16:38:13 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231151AbhCKVhi (ORCPT ); Thu, 11 Mar 2021 16:37:38 -0500 Received: from mail-wr1-x449.google.com (mail-wr1-x449.google.com [IPv6:2a00:1450:4864:20::449]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 772CCC061574 for ; Thu, 11 Mar 2021 13:37:38 -0800 (PST) Received: by mail-wr1-x449.google.com with SMTP id p15so10029562wre.13 for ; Thu, 11 Mar 2021 13:37:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=5DZPocqARvJ2VhBFUP59zWFPA2pzWUkM0o/y8pYmFsA=; b=ACyAQPWmvq+dZylG5VI/jRYY6sQl1IZ6N4PT9Rdc/yzYMPJCYHuZdkYZh48JjAoggg WDUsxkJTRWWxF21I/IBkPZ5PFV/REw+wSsHkD1LGe7hRMZBxYxoEr8OrauLf2u9Xunvo mWYL3QzNGQ4lwNk8hGnYa8o1ZQ0KfaSGux4X1KxyyJgWv1lny7dQ5U7GhTHrQ8bK6fwZ Qrvwfh2ATxJNUa2nH7Heg88Q8APRejiLmsfyaKEU8xL69rIZNGSzM/Zwig7d6nGC8FTM EXEV0MFip+6ZHsabX/6RgRI+uIYIxcvjUVg/3RP6XP7c+BTrMZI9U4ZINfu0RMNHfdfy c9qQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=5DZPocqARvJ2VhBFUP59zWFPA2pzWUkM0o/y8pYmFsA=; b=FFBawqvTEbmE8L4mMs0AvfQxIjL8cYOEKYJLlOzInIxZH56wuMtMcJlT58yRynaQf/ KCrT2G7plAvcHjrk5WC3GNg24hPBi6f7oyEg54VNvAHmYgXBJQ1imiqMCfVXCmRWsN3b pq59H6WjELNLCo1cn/82gEI4jHN6/DcnXQHNtTO7bPEt5/OpQmdpLJiMRYFJuCdr2pul WOfSLicwlmH8vOT5l74I3BBwiCUXTQAsC56DQS1mw17ZSWAhbEu75UdJgqDfH7jdcm73 V2zHJ/A66ngyACdxZ5J/VaswFs+N8P0kvnSfC1VgQlrs48lrhENl7sdKON//MCcfgOtO 1BWg== X-Gm-Message-State: AOAM532IFQBWgdgjoRlb3HKejJg+9vWnFZkscUAwLN0Xo17f1CsJH/7A Gu3CxeEHpyQoHfnoCTzUCd1k2a9rRW4hQaln X-Google-Smtp-Source: ABdhPJzrOToWEZY02T05UeRMCgcgQkkWvheRBtD+HjN401dMUC2SAN/NS8E97IDpd+hPV/fER6amECyXFjDeYS3F X-Received: from andreyknvl3.muc.corp.google.com ([2a00:79e0:15:13:95a:d8a8:4925:42be]) (user=andreyknvl job=sendgmr) by 2002:a5d:58ce:: with SMTP id o14mr5622327wrf.4.1615498657160; Thu, 11 Mar 2021 13:37:37 -0800 (PST) Date: Thu, 11 Mar 2021 22:37:17 +0100 In-Reply-To: Message-Id: Mime-Version: 1.0 References: X-Mailer: git-send-email 2.31.0.rc2.261.g7f71774620-goog Subject: [PATCH 05/11] kasan: docs: update boot parameters section From: Andrey Konovalov To: Andrew Morton , Alexander Potapenko , Marco Elver Cc: Andrey Ryabinin , Dmitry Vyukov , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrey Konovalov Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Update the "Boot parameters" section in KASAN documentation: - Mention panic_on_warn. - Mention kasan_multi_shot and its interaction with panic_on_warn. - Clarify kasan.fault=panic interaction with panic_on_warn. - A readability clean-up. Signed-off-by: Andrey Konovalov --- Documentation/dev-tools/kasan.rst | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index 5fe43489e94e..2f939241349d 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -174,10 +174,16 @@ call_rcu() and workqueue queuing. Boot parameters ~~~~~~~~~~~~~~~ +KASAN is affected by the generic ``panic_on_warn`` command line parameter. +When it is enabled, KASAN panics the kernel after printing a bug report. + +By default, KASAN prints a bug report only for the first invalid memory access. +With ``kasan_multi_shot``, KASAN prints a report on every invalid access. This +effectively disables ``panic_on_warn`` for KASAN reports. + Hardware tag-based KASAN mode (see the section about various modes below) is intended for use in production as a security mitigation. Therefore, it supports -boot parameters that allow to disable KASAN competely or otherwise control -particular KASAN features. +boot parameters that allow disabling KASAN or controlling its features. - ``kasan=off`` or ``=on`` controls whether KASAN is enabled (default: ``on``). @@ -185,8 +191,8 @@ particular KASAN features. traces collection (default: ``on``). - ``kasan.fault=report`` or ``=panic`` controls whether to only print a KASAN - report or also panic the kernel (default: ``report``). Note, that tag - checking gets disabled after the first reported bug. + report or also panic the kernel (default: ``report``). The panic happens even + if ``kasan_multi_shot`` is enabled. Implementation details ---------------------- -- 2.31.0.rc2.261.g7f71774620-goog