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=-17.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 A8375C5B57D for ; Wed, 3 Jul 2019 01:08:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78E0D2053B for ; Wed, 3 Jul 2019 01:08:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="PHzIGGfX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727423AbfGCBID (ORCPT ); Tue, 2 Jul 2019 21:08:03 -0400 Received: from mail-oi1-f202.google.com ([209.85.167.202]:38630 "EHLO mail-oi1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727408AbfGCBIC (ORCPT ); Tue, 2 Jul 2019 21:08:02 -0400 Received: by mail-oi1-f202.google.com with SMTP id u8so363384oie.5 for ; Tue, 02 Jul 2019 18:08:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=kOX/b18nZuUFLUmGmTpl546hS1EqehWOvqAy79HryjA=; b=PHzIGGfXetYTXGzyTnFKvYWj/S64EJ84TRcojkaEZ3zefgwEC4LsicdhwrkL2ldmKB gLAW7FqH4fV0fpD5nRCgP2WElmI4pBZ/bAxq8fzbpmZBPLR1WKxd5oKCsf/crj/4jdmt naAfJALZxW8RSMccuFYHpwcKTyChfjibhUexOeeOVyiukx4Qzs0d00o8Po9sq0lQhsZc bm/KmFcPSVoxiXPQBDZhlN7bv5zwQM8qNbDTCdGKs3xItoELX3CvzNDL5wVT124uTSa/ lgeB7jg/Jrdoqhn89hRdD8AY7lVg4ofRKcOwK/vqZ25QdXZj1E42OnQVfw8QJyKJo1bo Nv4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=kOX/b18nZuUFLUmGmTpl546hS1EqehWOvqAy79HryjA=; b=Xim+ij1htI45lPV5I9O53/E8RM0QKBS4xaUmsjaieUzQ3fsUbGIDGdQtMriVUaNY3g xMiUJEtemSjtgMnLjQG8Z9r+OQFSTo9JAu9hhP+VubtVKafYFfuRtNhSopY247+gNNve tNZ34a1OGFYI5D9H1YokaCxahZK/Kj/LhCpjkqBgChZUUaP0dqfgWdWt3lzqEmL63ro1 oN+26uTuGrc2U/rSPTNVbuO3LeLnY1502dQVivY2hOybYvMC0Z2I4y0fChl4iLd2UUMk 7PSJWnQ4I3sTElD5fNpx/eW58zmC2JHQK12AwRGmCEiTV4mW2ahoqh0BtfLRcaGO1OZA tsCg== X-Gm-Message-State: APjAAAVgHy9JHVpSBYYmdXdATgqfSNlE5PU6P+jEA6Z/0Ks1bgFPOHqS vDZhh22QsDqavn6gb/VbEx3K7AjTAg== X-Google-Smtp-Source: APXvYqy7Ahm6xsIBAxbvahe7MpZfFhmQrJUfui7MRkmuGNA2r+KtX7OKAP2SMxHgy3LSHG1zLsGv5aFPcA== X-Received: by 2002:a63:bd0a:: with SMTP id a10mr18703895pgf.55.1562109188555; Tue, 02 Jul 2019 16:13:08 -0700 (PDT) Date: Tue, 2 Jul 2019 16:13:02 -0700 Message-Id: <20190702231302.60727-1-nhuck@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH] arm64: mm: Fix dead assignment of old_pte From: Nathan Huckleberry To: catalin.marinas@arm.com, will@kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Nathan Huckleberry Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When analyzed with the clang static analyzer the following warning occurs line 251, column 2 Value stored to 'old_pte' is never read This warning is repeated every time pgtable.h is included by another file and produces ~3500 extra warnings. Moving old_pte into preprocessor guard. Cc: clang-built-linux@googlegroups.com Signed-off-by: Nathan Huckleberry --- arch/arm64/include/asm/pgtable.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index fca26759081a..42ca4fc67f27 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -238,8 +238,6 @@ extern void __sync_icache_dcache(pte_t pteval); static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte) { - pte_t old_pte; - if (pte_present(pte) && pte_user_exec(pte) && !pte_special(pte)) __sync_icache_dcache(pte); @@ -248,8 +246,11 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, * hardware updates of the pte (ptep_set_access_flags safely changes * valid ptes without going through an invalid entry). */ + #if IS_ENABLED(CONFIG_DEBUG_VM) + pte_t old_pte; + old_pte = READ_ONCE(*ptep); - if (IS_ENABLED(CONFIG_DEBUG_VM) && pte_valid(old_pte) && pte_valid(pte) && + if (pte_valid(old_pte) && pte_valid(pte) && (mm == current->active_mm || atomic_read(&mm->mm_users) > 1)) { VM_WARN_ONCE(!pte_young(pte), "%s: racy access flag clearing: 0x%016llx -> 0x%016llx", @@ -258,6 +259,7 @@ static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, "%s: racy dirty state clearing: 0x%016llx -> 0x%016llx", __func__, pte_val(old_pte), pte_val(pte)); } + #endif set_pte(ptep, pte); } -- 2.22.0.410.gd8fdbe21b5-goog