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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 3D083C48BE5 for ; Mon, 21 Jun 2021 08:54:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 25ECB61164 for ; Mon, 21 Jun 2021 08:54:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230335AbhFUI44 (ORCPT ); Mon, 21 Jun 2021 04:56:56 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:55022 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230235AbhFUI4W (ORCPT ); Mon, 21 Jun 2021 04:56:22 -0400 Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id DBFA421A5F; Mon, 21 Jun 2021 08:54:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1624265647; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=z29NiOZnPCs3ZLnHpWRg/UID2y5f48OSKobcQVNlz/8=; b=LCfYWum8p/HMD3YLqAgxSJhd8QQx3lFwHSuJ6bgkJzfOP7xoleVw0UyDlAqNX78HOIBUin W7oTmhhYv9BVkgZkpiU4AR28n0y8rbS596r8hmNFgeSVeIwy0R6q9N+OnXeySnybx8hUWs TcDOiVEbb/wooP5tbOU+G468s4Ao8AM= Received: from suse.cz (unknown [10.100.216.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 32B7EA3BA2; Mon, 21 Jun 2021 08:54:07 +0000 (UTC) Date: Mon, 21 Jun 2021 10:54:06 +0200 From: Petr Mladek To: Andrew Morton , Chris Down Cc: linux-kernel@vger.kernel.org, Jessica Yu , Sergey Senozhatsky , John Ogness , Steven Rostedt , Greg Kroah-Hartman , Johannes Weiner , Kees Cook , Andy Shevchenko , Rasmus Villemoes , kernel-team@fb.com Subject: Re: [PATCH v7 0/5] printk: Userspace format indexing support Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu 2021-06-17 12:10:43, Petr Mladek wrote: > On Tue 2021-06-15 17:52:20, Chris Down wrote: > > We have a number of systems industry-wide that have a subset of their > > functionality that works as follows: > > > > 1. Receive a message from local kmsg, serial console, or netconsole; > > 2. Apply a set of rules to classify the message; > > 3. Do something based on this classification (like scheduling a > > remediation for the machine), rinse, and repeat. > > > > This provides a solution to the issue of silently changed or deleted > > printks: we record pointers to all printk format strings known at > > compile time into a new .printk_index section, both in vmlinux and > > modules. At runtime, this can then be iterated by looking at > > /printk/index/, which emits the following format, both > > readable by humans and able to be parsed by machines: > > > > $ head -1 vmlinux; shuf -n 5 vmlinux > > # filename:line function "format" > > <5> block/blk-settings.c:661 disk_stack_limits "%s: Warning: Device %s is misaligned\n" > > <4> kernel/trace/trace.c:8296 trace_create_file "Could not create tracefs '%s' entry\n" > > <6> arch/x86/kernel/hpet.c:144 _hpet_print_config "hpet: %s(%d):\n" > > <6> init/do_mounts.c:605 prepare_namespace "Waiting for root device %s...\n" > > <6> drivers/acpi/osl.c:1410 acpi_no_auto_serialize_setup "ACPI: auto-serialization disabled\n" > > > > This mitigates the majority of cases where we have a highly-specific > > printk which we want to match on, as we can now enumerate and check > > whether the format changed or the printk callsite disappeared entirely > > in userspace. This allows us to catch changes to printks we monitor > > earlier and decide what to do about it before it becomes problematic. > > > > There is no additional runtime cost for printk callers or printk itself, > > and the assembly generated is exactly the same. > > > > Chris Down (5): > > string_helpers: Escape double quotes in escape_special > > printk: Straighten out log_flags into printk_info_flags > > printk: Rework parse_prefix into printk_parse_prefix > > printk: Userspace format indexing support > > printk: index: Add indexing support to dev_printk > > The patchset looks ready for linux-next from my POV. I could fixup the > messages as suggested by Andy when pushing. > > Well, I would still like to get acks from: > > + Andy for the 1st patch > + Jessica for the changes in the module loader code in 4th patch. They provided the Acks, so that we could push it. Andrew, this patchset depends on seq_file and string_helpers changes that are in -mm tree: lib-string_helpers-switch-to-use-bit-macro.patch lib-string_helpers-move-escape_np-check-inside-else-branch-in-a-loop.patch lib-string_helpers-drop-indentation-level-in-string_escape_mem.patch lib-string_helpers-introduce-escape_na-for-escaping-non-ascii.patch lib-string_helpers-introduce-escape_nap-to-escape-non-ascii-and-non-printable.patch lib-string_helpers-allow-to-append-additional-characters-to-be-escaped.patch lib-test-string_helpers-print-flags-in-hexadecimal-format.patch lib-test-string_helpers-get-rid-of-trailing-comma-in-terminators.patch lib-test-string_helpers-add-test-cases-for-new-features.patch maintainers-add-myself-as-designated-reviewer-for-generic-string-library.patch seq_file-introduce-seq_escape_mem.patch seq_file-add-seq_escape_str-as-replica-of-string_escape_str.patch seq_file-convert-seq_escape-to-use-seq_escape_str.patch nfsd-avoid-non-flexible-api-in-seq_quote_mem.patch seq_file-drop-unused-_escape_mem_ascii.patch Would you mind to take this patchset via -mm tree as well, please? You were not in CC. Should Chris send v8 with all the Acks and you in CC? Best Regards, Petr