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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 E44B4C433DF for ; Wed, 14 Oct 2020 10:42:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 533352173E for ; Wed, 14 Oct 2020 10:42:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="fg1wqkFq" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388181AbgJNKmE (ORCPT ); Wed, 14 Oct 2020 06:42:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52744 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387774AbgJNKmB (ORCPT ); Wed, 14 Oct 2020 06:42:01 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 41E35C061755 for ; Wed, 14 Oct 2020 03:42:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=LJVu+MlSQ135OMTrfXm0jmGtS2Z0lA/6W3TfbIbUafc=; b=fg1wqkFqIpJ6+zIvUU2P4p4vpk CRX+M4+TIKpl8LpbBxOY+4593crTmzXahsH6EpTqlT8cznm3MsFD8YsJJmyZDWWadZYvTmcMpBEV3 y8k/mCTSoEAi7uXb1d56Za1N7Pxdk0zCQzTLc6GKoE7RgrWT5BnwSU9Spsd1gNRPjLQk9LVgKNCn6 LEaGbS68TENVqpMAMKGIhIJOy3n9BWaI1lJfkFGNp7l76c/kl00tT7oY8RBhmyBOKz2xidDdrDHb6 UN7ll7n72py8kE+fZqLpGhPDjUF8N9h7adKOm1bhuxLjJ1vN+VlvHxHinZ3vJ2LWtczn4FdGgSMaz 0Cjwhzkg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kSeEB-0005xu-Lk; Wed, 14 Oct 2020 10:41:51 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 9DBC23069AE; Wed, 14 Oct 2020 12:41:48 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 7BC3C20696FD8; Wed, 14 Oct 2020 12:41:48 +0200 (CEST) Date: Wed, 14 Oct 2020 12:41:48 +0200 From: Peter Zijlstra To: Dave Hansen Cc: "Brown, Len" , Andy Lutomirski , "Bae, Chang Seok" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , X86 ML , "Liu, Jing2" , "Shankar, Ravi V" , LKML Subject: Re: [RFC PATCH 13/22] x86/fpu/xstate: Expand dynamic user state area on first use Message-ID: <20201014104148.GD2628@hirez.programming.kicks-ass.net> References: <20201001203913.9125-1-chang.seok.bae@intel.com> <20201001203913.9125-14-chang.seok.bae@intel.com> 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 On Tue, Oct 13, 2020 at 03:43:59PM -0700, Dave Hansen wrote: > On 10/13/20 3:31 PM, Brown, Len wrote: > > vmalloc() does not fail, and does not return an error, and so there is no concept > > of returning a signal. > > Well, the order-0 allocations are no-fail, as are the vmalloc kernel > structures and the page tables that might have to be allocated. But, > that's not guaranteed to be in place *forever*. I think we still need > to check for and handle allocation failures, even if they're not known > to be possible today. Quite, on top of that, we could run out of vmalloc space (unlikely, but sitll). You really have to deal with vmalloc() failing.