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=-23.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=ham 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 A2F65C433FE for ; Wed, 9 Dec 2020 13:51:57 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 33C5B23B51 for ; Wed, 9 Dec 2020 13:51:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 33C5B23B51 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 545708D001F; Wed, 9 Dec 2020 08:51:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4FEB18D001E; Wed, 9 Dec 2020 08:51:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3E3FE8D001F; Wed, 9 Dec 2020 08:51:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0094.hostedemail.com [216.40.44.94]) by kanga.kvack.org (Postfix) with ESMTP id 27E438D001E for ; Wed, 9 Dec 2020 08:51:56 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id E534D1EE6 for ; Wed, 9 Dec 2020 13:51:55 +0000 (UTC) X-FDA: 77573882190.29.war35_3510268273f0 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id B82C0180868E5 for ; Wed, 9 Dec 2020 13:51:55 +0000 (UTC) X-HE-Tag: war35_3510268273f0 X-Filterd-Recvd-Size: 4538 Received: from mail-pl1-f193.google.com (mail-pl1-f193.google.com [209.85.214.193]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Wed, 9 Dec 2020 13:51:55 +0000 (UTC) Received: by mail-pl1-f193.google.com with SMTP id j1so966345pld.3 for ; Wed, 09 Dec 2020 05:51:55 -0800 (PST) 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=w4MkXK3tdvL2KD1xeLvIGtLJ1l3YTvntIB2NHLxLGEE=; b=odoVmjOP5a21hkZKPqPD/kvmnmP82iAFi1Q+sOKq2H0z9qS/cCOEvhgqlRHaQ67AFM DG2vpSkIpTZGwYASYEyDcVchdt1haJQxT9dxOP14VMEREenxN1KP1Gk3mGy6k72rtzVc 9B4bb+pXD2vNGb/62RHKL5cSHH+1ps9YN3T+vPc/fWvg+Uh8kkuFxMdouOMpAVgB9J+g 96HhPYEGFo/bz3ikWU/5wZbXvwGJoF88/joRN2tqIWzghtffM+W86TrX3Lq9jgbyihXV /uPbATPaMFQAD2ASY4crtD+Lp7aX0lFTPi48BE2YM2VGagaKPSiRGEiGMBjFRZOaxcx2 kOpw== 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=w4MkXK3tdvL2KD1xeLvIGtLJ1l3YTvntIB2NHLxLGEE=; b=O3EKHEVlEDrr1IqDTpltg1rhruLK8C4sIZZGB0MZd/hxuQOqI+xZrtkHwQ9Ig64zkH FPUcSAv9UHGy08aWopSakL66xMF6MxSEnOBMODyuQFjBOLWJVRKho2DP7Q4DnQTDCZZu l7s89Z0p2s9+1cdsFqYlBbinGVrKJUIwZQBudqDtIys4SOXu2f/nu8OkcrQV38zqzkaW NaNSeeS6X4MFrgVnUiRiPgBln3NdtKemeSsJyjenOHRfQCAyPa7sqIyN/7i46llSp+gL x/F4FieQyBSZXpIDrnY9F1094LwJcAnPVYaDDGXeXT3oRFvlXEdY4rg8iWSgTdqtlq2P vS9A== X-Gm-Message-State: AOAM533hSnfQ107UP/3yJE1yWBcvceWooE6yLhi8Z/DBTXHdBDFBDOjs /eW1/JnX7haocRJFauQQbrJV8SvGfXQU2cLx7lWwuw== X-Google-Smtp-Source: ABdhPJxBsezEc8STQRX9tDLqC2eWAW+AY62pnK3hgFS5UbphzvcBPKkjl1yxpmR7/r0a7FlrApk+uK6ScI0166W5tFg= X-Received: by 2002:a17:902:900c:b029:da:b7a3:d83a with SMTP id a12-20020a170902900cb02900dab7a3d83amr2010763plp.57.1607521913989; Wed, 09 Dec 2020 05:51:53 -0800 (PST) MIME-Version: 1.0 References: <20201209100152.2492072-1-dvyukov@google.com> In-Reply-To: <20201209100152.2492072-1-dvyukov@google.com> From: Andrey Konovalov Date: Wed, 9 Dec 2020 14:51:43 +0100 Message-ID: Subject: Re: [PATCH] kcov: don't instrument with UBSAN To: Dmitry Vyukov Cc: Andrew Morton , kasan-dev , LKML , Linux Memory Management List , Stephen Rothwell , Marco Elver Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Dec 9, 2020 at 11:01 AM Dmitry Vyukov wrote: > > Both KCOV and UBSAN use compiler instrumentation. If UBSAN detects a bug > in KCOV, it may cause infinite recursion via printk and other common > functions. We already don't instrument KCOV with KASAN/KCSAN for this > reason, don't instrument it with UBSAN as well. > > As a side effect this also resolves the following gcc warning: > > conflicting types for built-in function '__sanitizer_cov_trace_switch'; > expected 'void(long unsigned int, void *)' [-Wbuiltin-declaration-mismatch] > > It's only reported when kcov.c is compiled with any of the sanitizers > enabled. Size of the arguments is correct, it's just that gcc uses 'long' > on 64-bit arches and 'long long' on 32-bit arches, while kernel type is > always 'long long'. > > Reported-by: Stephen Rothwell > Suggested-by: Marco Elver > Signed-off-by: Dmitry Vyukov > --- > kernel/Makefile | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/kernel/Makefile b/kernel/Makefile > index aac15aeb9d69..efa42857532b 100644 > --- a/kernel/Makefile > +++ b/kernel/Makefile > @@ -34,8 +34,11 @@ KCOV_INSTRUMENT_extable.o := n > KCOV_INSTRUMENT_stacktrace.o := n > # Don't self-instrument. > KCOV_INSTRUMENT_kcov.o := n > +# If sanitizers detect any issues in kcov, it may lead to recursion > +# via printk, etc. > KASAN_SANITIZE_kcov.o := n > KCSAN_SANITIZE_kcov.o := n > +UBSAN_SANITIZE_kcov.o := n > CFLAGS_kcov.o := $(call cc-option, -fno-conserve-stack) -fno-stack-protector > > obj-y += sched/ > -- > 2.29.2.576.ga3fc446d84-goog > Reviewed-by: Andrey Konovalov