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=-8.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8A178C43331 for ; Fri, 3 Apr 2020 16:20:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59E2B2077D for ; Fri, 3 Apr 2020 16:20:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="T3Upy+I8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404348AbgDCQUu (ORCPT ); Fri, 3 Apr 2020 12:20:50 -0400 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:33590 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728020AbgDCQUu (ORCPT ); Fri, 3 Apr 2020 12:20:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585930848; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=LluwbzYPZTeVhlFwEl3Fq8+v9AvRnqXZTrSsmeMHE2I=; b=T3Upy+I8SHtu52Xh4otZm/XKkqmSNJWGXsmp+sf5lZwOzuagmETuCHOcLmLbJVeoaZ9YfK Jh5Kcl09Qx8AL2oQQEGnF2mP3ptAV58ok3noTFGJtMPNsZna/sU9CTvBUY1ADdBP5zssaJ 8SkcGYEqEXqv/xH6P3NwMXcbICNjpxw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-98-oxMaVJn4NUuZOhmFbeg-Xg-1; Fri, 03 Apr 2020 12:20:44 -0400 X-MC-Unique: oxMaVJn4NUuZOhmFbeg-Xg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id E58B1100550D; Fri, 3 Apr 2020 16:20:42 +0000 (UTC) Received: from treble (ovpn-118-100.rdu2.redhat.com [10.10.118.100]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 356CB18A85; Fri, 3 Apr 2020 16:20:41 +0000 (UTC) Date: Fri, 3 Apr 2020 11:20:39 -0500 From: Josh Poimboeuf To: Nick Desaulniers Cc: peterz@infradead.org, Kamalesh Babulal , Matt Helsley , Randy Dunlap , Jonathan Corbet , Mauro Carvalho Chehab , Petr Mladek , Raphael Gault , linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH v2] objtool: Documentation: document UACCESS warnings Message-ID: <20200403162039.fubfeblv3x5pmphn@treble> References: <20200326134701.GA118458@rlwimi.vmware.com> <20200326183707.238474-1-ndesaulniers@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200326183707.238474-1-ndesaulniers@google.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 26, 2020 at 11:37:06AM -0700, Nick Desaulniers wrote: > Compiling with Clang and CONFIG_KASAN=y was exposing a few warnings: > call to memset() with UACCESS enabled > > Document how to fix these for future travelers. > > Link: https://github.com/ClangBuiltLinux/linux/issues/876 > Suggested-by: Kamalesh Babulal > Suggested-by: Matt Helsley > Suggested-by: Peter Zijlstra > Suggested-by: Randy Dunlap > Signed-off-by: Nick Desaulniers > --- > Changes V1 -> V2: > * fix typo of listing uaccess_enable() twice rather than > uaccess_disable() as per Matt and Kamalesh. > * fix type of "should called" to "should be called" as per Randy. > * Mention non-obvious compiler instrumentation ie. -pg/mcount > -mfentry/fentry via tracing as per Peter. > * Add sentence "It also helps verify..." > * Add potential fix "1) remove explicit..." Thanks, adding this one to the queue for tip. -- Josh