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[209.132.180.67]) by mx.google.com with ESMTP id e11si3944696oif.131.2020.04.03.09.21.38; Fri, 03 Apr 2020 09:21:50 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=T3Upy+I8; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404234AbgDCQUu (ORCPT + 99 others); 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