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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC4ACC433FE for ; Fri, 21 Oct 2022 13:23:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230442AbiJUNW6 (ORCPT ); Fri, 21 Oct 2022 09:22:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229839AbiJUNW4 (ORCPT ); Fri, 21 Oct 2022 09:22:56 -0400 Received: from mail-ed1-x530.google.com (mail-ed1-x530.google.com [IPv6:2a00:1450:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 379432527E8 for ; Fri, 21 Oct 2022 06:22:55 -0700 (PDT) Received: by mail-ed1-x530.google.com with SMTP id b12so5778935edd.6 for ; Fri, 21 Oct 2022 06:22:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=aTHKaZCiit3Ul01YDGFtP12Qx3iKFThlFmh66angHUc=; b=fiKApkDmp6tyrlKol5Kb4NK0cPmQ+F4mux4TjM51jKFVSqtU6Qcoizqk9zF9Af4k2Z AKGDRbIELDjq/0ek3b+/CKd+oxjLLIYsqPBU10Uok+k5CHQBv7lsiYRdZDgD1bRcUIaP UC9VBncfA7Mi+4PPHP+68gNwVaxFA0p57NuGRrG/4R3Wdb2PSpqrFJxiRMIUBQDUJBdW TsTG7SLdkLaoyy5P2famgp01xlnUgT7yVEYfVjcheym6Jl6U6GUU/ruy27ZPy6b328qV I9ixf1Q9xGAVdSAAJqyExDRc4TNobtnPbGnlmNp/QxAFiaffbdG06X3xPF0wPavtg7lQ TsHQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=aTHKaZCiit3Ul01YDGFtP12Qx3iKFThlFmh66angHUc=; b=gqXa0yAw2MkJMtGOt3ujDYEJ+8GWSILSsm1cs67MO+b6+8t4nH0fmlBXNtF1q+5lsF 8+/gkcKMrXmyC55Brn1xAvysLg8VizgqK9WfIttgpQqLPg3NG1mtB1K8tFx8hXnzZZnx xVBhtlVUn9PdrtRMnbF/hRMBi9fbWfmZjnApWMrBGRUln6Mi1Xkl5WjKjT2CQg/QaBew F61GdkELWm0r5FcdsrSkjSYaaL9NQgpZVTAZsF48X5+10Fy/+9kmFobr+RtMzB6iZSjn BMoRitGRgzXsSxOUveFZ0Wf6l6ZukSpSlHmSb5Z7lluju5J9NXkKWyQdZ0z1aqNJ3uv6 MFJA== X-Gm-Message-State: ACrzQf0dLf4M5eqnYExcYmO89cy/7VhOxOokMuPfjAG9+G7/4SpfqOe8 e2K/POimN/kfE4Tqa/cKj0Iy7EB5kmooow== X-Google-Smtp-Source: AMsMyM5syXbdOdYghEOb2IW3LQ96J2f99FQy3tqIx70r6rE6I/rZ/NQEu6JeomSCSuBNsoX5g4Hi0A== X-Received: by 2002:a05:6402:28b7:b0:459:3115:aa07 with SMTP id eg55-20020a05640228b700b004593115aa07mr16798195edb.280.1666358573617; Fri, 21 Oct 2022 06:22:53 -0700 (PDT) Received: from andrea ([77.89.52.45]) by smtp.gmail.com with ESMTPSA id u9-20020a1709061da900b0078e0973d1f5sm10694622ejh.0.2022.10.21.06.22.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Oct 2022 06:22:53 -0700 (PDT) Date: Fri, 21 Oct 2022 15:22:48 +0200 From: Andrea Parri To: Tong Tiangen Cc: Guo Ren , Jisheng Zhang , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] riscv: fix race when vmap stack overflow Message-ID: References: <20221019154727.2395-1-jszhang@kernel.org> 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 Hi Tong, > > > I use atomic_set_release here, because I need earlier memory > > > operations finished to make sure the sp is ready then set the spin > > > flag. > Consider this implementation:) > > smp_store_mb(&spin_shadow_stack, 0); smp_store_mb() has "WRITE_ONCE(); smp_mb()" semantics; so it doesn't guarantee that the store to spin_shadow_stack is ordered after program -order earlier memory accesses. Andrea