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=-16.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_1 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 BE180C433F5 for ; Thu, 16 Sep 2021 03:42:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A14726112E for ; Thu, 16 Sep 2021 03:42:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234218AbhIPDnr (ORCPT ); Wed, 15 Sep 2021 23:43:47 -0400 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:56456 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233630AbhIPDnq (ORCPT ); Wed, 15 Sep 2021 23:43:46 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=yun.wang@linux.alibaba.com;NM=1;PH=DS;RN=20;SR=0;TI=SMTPD_---0UoXWyLM_1631763742; Received: from testdeMacBook-Pro.local(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0UoXWyLM_1631763742) by smtp.aliyun-inc.com(127.0.0.1); Thu, 16 Sep 2021 11:42:23 +0800 Subject: Re: [PATCH] x86: Increase exception stack sizes To: Peter Zijlstra Cc: Dave Hansen , Dave Hansen , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , "H. Peter Anvin" , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , "open list:X86 MM" , "open list:BPF (Safe dynamic programs and tools)" , "open list:BPF (Safe dynamic programs and tools)" References: <09777a57-a771-5e17-7e17-afc03ea9b83b@linux.alibaba.com> <4f63c8bc-1d09-1717-cf81-f9091a9f9fb0@linux.alibaba.com> <18252e42-9c30-73d4-e3bb-0e705a78af41@intel.com> <4cba7088-f7c8-edcf-02cd-396eb2a56b46@linux.alibaba.com> <09d0190b-f2cc-9e64-4d3a-4eb0def22b7b@linux.alibaba.com> From: =?UTF-8?B?546L6LSH?= Message-ID: <0278349e-3a6d-9ebd-6cc3-490fb99d1990@linux.alibaba.com> Date: Thu, 16 Sep 2021 11:42:22 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/9/15 δΈ‹εˆ11:19, Peter Zijlstra wrote: > On Wed, Sep 15, 2021 at 03:34:20PM +0800, ηŽ‹θ΄‡ wrote: >> Hi, Dave, Peter >> >> What if we just increase the stack size when ftrace enabled? > > I think we can do an unconditional increase. But please first test that > guard page patch :-) Nice~ let's focus on the guard one firstly. Regards, Michael Wang > > --- > Subject: x86: Increase exception stack sizes > From: Peter Zijlstra > Date: Wed Sep 15 16:19:46 CEST 2021 > > It turns out that a single page of stack is trivial to overflow with > all the tracing gunk enabled. Raise the exception stacks to 2 pages, > which is still half the interrupt stacks, which are at 4 pages. > > Reported-by: Michael Wang > Signed-off-by: Peter Zijlstra (Intel) > --- > arch/x86/include/asm/page_64_types.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- a/arch/x86/include/asm/page_64_types.h > +++ b/arch/x86/include/asm/page_64_types.h > @@ -15,7 +15,7 @@ > #define THREAD_SIZE_ORDER (2 + KASAN_STACK_ORDER) > #define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER) > > -#define EXCEPTION_STACK_ORDER (0 + KASAN_STACK_ORDER) > +#define EXCEPTION_STACK_ORDER (1 + KASAN_STACK_ORDER) > #define EXCEPTION_STKSZ (PAGE_SIZE << EXCEPTION_STACK_ORDER) > > #define IRQ_STACK_ORDER (2 + KASAN_STACK_ORDER) >