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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH, USER_AGENT_MUTT 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 B8C1DC28CC2 for ; Wed, 29 May 2019 16:25:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9243523D60 for ; Wed, 29 May 2019 16:25:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559147137; bh=1LYbnDID6+i96jGpOccylgW14e+dv8wtRA6L2mHibJo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=hKA05IZeAF6SL3canvUT1l4x49kvDICi556tgAKBSLsR4FjNM3u+/RKq4HJxFTQ9O 4kHrJnkUV53U/izRTVuhqHD76sk0zO9V5G4eYsZUXYyjz6IhWB5IKwgNOdo+QsckJB AtVBUMDTYyFe6CgOVOnqWR7HXlXCuZ8jEVe/o5Rg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727106AbfE2QZg (ORCPT ); Wed, 29 May 2019 12:25:36 -0400 Received: from mx2.suse.de ([195.135.220.15]:60150 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726062AbfE2QZf (ORCPT ); Wed, 29 May 2019 12:25:35 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 206D5ADEA; Wed, 29 May 2019 16:25:34 +0000 (UTC) Date: Wed, 29 May 2019 18:25:32 +0200 From: Michal Hocko To: Dianzhang Chen Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/slab_common.c: fix possible spectre-v1 in kmalloc_slab() Message-ID: <20190529162532.GG18589@dhcp22.suse.cz> References: <1559133448-31779-1-git-send-email-dianzhangchen0@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1559133448-31779-1-git-send-email-dianzhangchen0@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 29-05-19 20:37:28, Dianzhang Chen wrote: [...] > @@ -1056,6 +1057,7 @@ struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) > if (!size) > return ZERO_SIZE_PTR; > > + size = array_index_nospec(size, 193); > index = size_index[size_index_elem(size)]; What is this 193 magic number? -- Michal Hocko SUSE Labs