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 B7D7CC433FE for ; Wed, 9 Dec 2020 10:50:25 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 40C2523B77 for ; Wed, 9 Dec 2020 10:50:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 40C2523B77 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 716DE8D0017; Wed, 9 Dec 2020 05:50:24 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6A2098D000B; Wed, 9 Dec 2020 05:50:24 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 591078D0017; Wed, 9 Dec 2020 05:50:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0099.hostedemail.com [216.40.44.99]) by kanga.kvack.org (Postfix) with ESMTP id 439698D000B for ; Wed, 9 Dec 2020 05:50:24 -0500 (EST) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 07DE28249980 for ; Wed, 9 Dec 2020 10:50:24 +0000 (UTC) X-FDA: 77573424768.11.bell61_5605411273ef Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin11.hostedemail.com (Postfix) with ESMTP id D8BD1180F8B81 for ; Wed, 9 Dec 2020 10:50:23 +0000 (UTC) X-HE-Tag: bell61_5605411273ef X-Filterd-Recvd-Size: 4466 Received: from mail-ot1-f65.google.com (mail-ot1-f65.google.com [209.85.210.65]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Wed, 9 Dec 2020 10:50:23 +0000 (UTC) Received: by mail-ot1-f65.google.com with SMTP id f16so878397otl.11 for ; Wed, 09 Dec 2020 02:50:23 -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=MX94nPIGSLB0DB1OT3/FAuNxRnHj49zF47rxa5iMU8o=; b=W7Tqu+ygMoLsbJuO8fIJ3Z4pUGKQ2nCjJL/PMN6uV27pkBIEghs5/4aKrZkPIhxlnE tYU9pi13MA2tIpLp65o3E+DOUWuw9ZneMAFSav0QKfw7sBoxe+CPDwX/iOtU/nwGB4by n+g51nPMhIgQ05m5INhaLTDqXHcZyviSwwFkeuOkJEcW9A6zC9Yn8ukI5fDwVMk2QqMT 41N8GA8j/K0ahPhpMmNqbuMGiK584SloMWNp57GQaNaiCG/vPOhLzPC/NXYfFDnq1K/l 3jkj8xtceGt8gojg6AGzP98X70ZQozsZJTZ9sW73QqG1YwdLURteTj/kzL5PUHiN4q/s Z7KQ== 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=MX94nPIGSLB0DB1OT3/FAuNxRnHj49zF47rxa5iMU8o=; b=IIS1nCrdvAk1iEutSAJFRScXgGnUqe273vHbfUwvWrFeTVLzw/dxlwMF4LdycQT2Tn LqWC0YJzYr2q/j0njXAUzzUn28sYrKiYZrCYRIC1hOrteo70dcvO4/E2Vsl8Ztxnwrde 6zC36+V2MT0UWCvyovD97/dR707rqYojWZFAEXpPlQxFtPLxznCE/k3F2Qdp1MhrYFqP 5rcjZliiUPSMiAfXDIp7ZrlIRtfavQHWL+C1RDjWniILMXXm/4Fz89jz498y0/ANaOwB HMiH3pMBSp/AN7AQV9rgtwIg8g2SA0cUuQqX9ENPTJg+Wd3bM83ZgwJRRPEqkjPizVZN MUvg== X-Gm-Message-State: AOAM53337MvroAmqWdu6pe5zX84d9NKOZASwlleKnkoz5sUg/SI8Lcwy euHnYnxZuIVGYzpLTWNtlBCIPNjpaCl1Z8ndguQbHQ== X-Google-Smtp-Source: ABdhPJwYF4a+AnOIU1i+Ui7MeZtCnCDQDRBoESBnuKWFpsyVHgeWmSWYC8U7DsgT974c6UPATBxTWO98mTgDzhaBjLg= X-Received: by 2002:a9d:7cc8:: with SMTP id r8mr1180342otn.233.1607511022660; Wed, 09 Dec 2020 02:50:22 -0800 (PST) MIME-Version: 1.0 References: <20201209100152.2492072-1-dvyukov@google.com> In-Reply-To: <20201209100152.2492072-1-dvyukov@google.com> From: Marco Elver Date: Wed, 9 Dec 2020 11:50:11 +0100 Message-ID: Subject: Re: [PATCH] kcov: don't instrument with UBSAN To: Dmitry Vyukov Cc: Andrew Morton , Andrey Konovalov , kasan-dev , LKML , Linux Memory Management List , Stephen Rothwell 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, 9 Dec 2020 at 11:01, 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 Acked-by: Marco Elver > --- > 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 >