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=-11.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 631DFC2D0A3 for ; Fri, 6 Nov 2020 12:57:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E3A70206D5 for ; Fri, 6 Nov 2020 12:57:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="PpYWw1Sr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727313AbgKFM5x (ORCPT ); Fri, 6 Nov 2020 07:57:53 -0500 Received: from mx2.suse.de ([195.135.220.15]:45650 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726939AbgKFM5w (ORCPT ); Fri, 6 Nov 2020 07:57:52 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1604667470; h=from:from:reply-to:subject:subject: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=8GDVDLs9bnVzNuwPnm3MLNtCohe/Mct9rfNb0ZEHf2E=; b=PpYWw1Sr89j/SA+RFrx9zebb/L0Vdt96uqH3Bdk1OQhHY7bOl6TxSbMgflcnhJAkApiLkm JKhp4ZQZ/co57COTDWkz85r3RcxjsrHoQkpDt0heb/f9oYKlZcJHRTx6WHRh9PuZwf0nUm UR5tHnwIgTQLWbKjA10imY9/lSWmw3c= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 1733CAD2B; Fri, 6 Nov 2020 12:57:50 +0000 (UTC) Date: Fri, 6 Nov 2020 13:57:49 +0100 From: Petr Mladek To: Lukas Bulwahn Cc: Sergey Senozhatsky , Steven Rostedt , John Ogness , Nathan Chancellor , Nick Desaulniers , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, kernel-janitors@vger.kernel.org, linux-safety@lists.elisa.tech Subject: Re: [PATCH] printk: remove unneeded dead-store assignment Message-ID: <20201106125749.GU20201@alley> References: <20201106034005.18822-1-lukas.bulwahn@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201106034005.18822-1-lukas.bulwahn@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 2020-11-06 04:40:05, Lukas Bulwahn wrote: > make clang-analyzer on x86_64 defconfig caught my attention with: > > kernel/printk/printk_ringbuffer.c:885:3: warning: > Value stored to 'desc' is never read [clang-analyzer-deadcode.DeadStores] > desc = to_desc(desc_ring, head_id); > ^ > > Commit b6cf8b3f3312 ("printk: add lockless ringbuffer") introduced > desc_reserve() with this unneeded dead-store assignment. > > As discussed with John Ogness privately, this is probably just some minor > left-over from previous iterations of the ringbuffer implementation. So, > simply remove this unneeded dead assignment to make clang-analyzer happy. > > As compilers will detect this unneeded assignment and optimize this anyway, > the resulting object code is identical before and after this change. > > No functional change. No change to object code. > > Signed-off-by: Lukas Bulwahn The patch is committed in printk/linux.git, branch for-5.10-trivial. It might still go into 5.10 when there is another important fix. Otherwise, it would need to wait for 5.11 merge window. Best Regards, Petr