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=-14.6 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_IN_DEF_DKIM_WL autolearn=unavailable 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 E7B3AC433E0 for ; Mon, 22 Jun 2020 17:23:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C1CDB20767 for ; Mon, 22 Jun 2020 17:23:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="T/gZ4H2J" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730041AbgFVRXI (ORCPT ); Mon, 22 Jun 2020 13:23:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55790 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729977AbgFVRXF (ORCPT ); Mon, 22 Jun 2020 13:23:05 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2CBAC061795 for ; Mon, 22 Jun 2020 10:23:05 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id h22so134375pjf.1 for ; Mon, 22 Jun 2020 10:23:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=BqM48ZdR4QdYBTv2c7+F0igShsRmPGqVwAJTalrh3Vo=; b=T/gZ4H2J+UpNQ96H4IQLTAW9jVMnZlvLzxm2OhJBDlYjOIQCD2FlzsoigqacLWJAhC FAIymS/2Mdmvf5jp+PMPTZPszQlLdMUtLLlxEwYzzRg8451YxoBJQ2B6yep7Gr3zpQtx oME5SyrfsBCu+p9qDBNWb5W0Ik4fADMMt3L3iqomKhLtenk4gH6tWYsAJe0N4bqlw6TY e4kzYPrOVngrkzYP4ZO7qK52KTWkEaDOe/Hc26SYciu91gstYIuQ457fS2tO+3Fhc++S J3tpbd0xhmS8RbKKoltaGvNLCIjSjHM0jjaUbZ0vQp8KhiEYCwyRbniMeg/jqRQHieMg 4n/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=BqM48ZdR4QdYBTv2c7+F0igShsRmPGqVwAJTalrh3Vo=; b=ZTV/+eXsFWnHDzYEmsrfoyuBq4aelQRw2/bcmz07wVU7F3dn1m4SSem2E+6QzyNEvq 1dAOGG31mG8k0n0D7UBSTvjAolzHgSoULPPb0ko6ReG7KK/hZQxnMSoYpqr7bB0b3k5X 7KHzrW4/GGs15xiyFKJu16MGKPN7PafmlE5BY/cmiymif5hdsrsw93xiLTM58/nZTPxl gyYR8up5AyfvRFJwgePmzOHMWAOqfZFLt7NhxF0FADe3q/E32egjDlJANWiYFo+H8KgK g4huNy2a1s4EpJEjHFoauoGZ8EKor0Agu1Kwsv2hFzz2RM3dnEUo8maiglZo/CyS41xC Pdnw== X-Gm-Message-State: AOAM533ZzZ8bW1QH8vai6OPqv210C3i9hVFil1wyRUKwlW1Os6MeK3j/ vKbl7ROruULLmFp9ZMgXshmzMOx20LmZ3MnBjwgjxw== X-Google-Smtp-Source: ABdhPJzO+nq25CgrrJ901vreSYdCENCWSbB928SD41OoQSYC+oteTUNy5xrcCBXr3eXVXoqswpT2QCJu88gHklh2Xeo= X-Received: by 2002:a17:90a:1e:: with SMTP id 30mr18013542pja.25.1592846584932; Mon, 22 Jun 2020 10:23:04 -0700 (PDT) MIME-Version: 1.0 References: <20200620033007.1444705-1-keescook@chromium.org> <20200620033007.1444705-11-keescook@chromium.org> In-Reply-To: <20200620033007.1444705-11-keescook@chromium.org> From: Nick Desaulniers Date: Mon, 22 Jun 2020 10:22:53 -0700 Message-ID: Subject: Re: [PATCH v2 10/16] KVM: PPC: Book3S PR: Remove uninitialized_var() usage To: Kees Cook Cc: LKML , Nathan Chancellor , Linus Torvalds , Miguel Ojeda , Alexander Potapenko , Joe Perches , Andy Whitcroft , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , drbd-dev@lists.linbit.com, linux-block@vger.kernel.org, b43-dev@lists.infradead.org, Network Development , Linux Doc Mailing List , linux-wireless , linux-ide@vger.kernel.org, linux-clk@vger.kernel.org, linux-spi@vger.kernel.org, Linux Memory Management List , clang-built-linux 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 On Fri, Jun 19, 2020 at 8:30 PM Kees Cook wrote: > > Using uninitialized_var() is dangerous as it papers over real bugs[1] > (or can in the future), and suppresses unrelated compiler warnings (e.g. > "unused variable"). If the compiler thinks it is uninitialized, either > simply initialize the variable or make compiler changes. As a precursor > to removing[2] this[3] macro[4], just remove this variable since it was > actually unused: > > arch/powerpc/kvm/book3s_pr.c:1832:16: warning: unused variable 'vrsave' [-Wunused-variable] > unsigned long vrsave; > ^ > > [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ > [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ > [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ > [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ > > Suggested-by: Nathan Chancellor > Fixes: f05ed4d56e9c ("KVM: PPC: Split out code from book3s.c into book3s_pr.c") > Signed-off-by: Kees Cook Reviewed-by: Nick Desaulniers > --- > arch/powerpc/kvm/book3s_pr.c | 3 --- > 1 file changed, 3 deletions(-) > > diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c > index ef54f917bdaf..ed12dfbf9bb5 100644 > --- a/arch/powerpc/kvm/book3s_pr.c > +++ b/arch/powerpc/kvm/book3s_pr.c > @@ -1828,9 +1828,6 @@ static int kvmppc_vcpu_run_pr(struct kvm_vcpu *vcpu) > { > struct kvm_run *run = vcpu->run; > int ret; > -#ifdef CONFIG_ALTIVEC > - unsigned long uninitialized_var(vrsave); > -#endif > > /* Check if we can run the vcpu at all */ > if (!vcpu->arch.sane) { > -- -- Thanks, ~Nick Desaulniers