From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9873 invoked by alias); 18 Apr 2016 14:49:23 -0000 Mailing-List: contact binutils-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: binutils-owner@sourceware.org Received: (qmail 9835 invoked by uid 89); 18 Apr 2016 14:49:22 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.5 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mail-pf0-f173.google.com Received: from mail-pf0-f173.google.com (HELO mail-pf0-f173.google.com) (209.85.192.173) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Mon, 18 Apr 2016 14:49:19 +0000 Received: by mail-pf0-f173.google.com with SMTP id n1so81688267pfn.2 for ; Mon, 18 Apr 2016 07:49:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=faIg6RtVIiP+2lUsvmM/ZIMl0zYV1UN/xE9ex7xZH9g=; b=GiRpLHv+kXsKJ7sHbbY3VR+4DKBdlhAIzWXrMqLUkE23pUHkKKVYzgDqavXYDNjU4G EmzHN6UQPyWBrlycjed/kw8dZmlkk1axY3jdPpsjVkGPSy3/UaruPaPpZzDkFkoNEfWZ PfPTdP2sq89TI0QHDOIKq6/nyv1mqXPACj8QgtXBNUF5290NG7iDXdoq4y+SIx5OzL4I heJawRjQqABAV4dI8p+BMyuRCz1BNAVpUubSQRZUREhtEWJdu7mWhv6Kz47CE+T8Ce7L 7cico9UqxcqVY196uj7CBWU2EyoiOTa9fdWvNjldSmMvtQrFWwPI0wogE95fgAihEOck o+bw== X-Gm-Message-State: AOPr4FUV1PviOUnOQYHlPgftk3JC4eMYpGDCj4Mb8f0sSk4Dt4sRLC9qzxA1MmZ/1yl9XA== X-Received: by 10.98.40.200 with SMTP id o191mr50314645pfo.83.1460990956557; Mon, 18 Apr 2016 07:49:16 -0700 (PDT) Received: from bubble.grove.modra.org (CPE-58-160-146-233.sa.bigpond.net.au. [58.160.146.233]) by smtp.gmail.com with ESMTPSA id t126sm12020325pfb.73.2016.04.18.07.49.15 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 18 Apr 2016 07:49:15 -0700 (PDT) Received: by bubble.grove.modra.org (Postfix, from userid 1000) id 3A25CEA0153; Tue, 19 Apr 2016 00:19:11 +0930 (ACST) Date: Mon, 18 Apr 2016 14:49:00 -0000 From: Alan Modra To: Richard Biener Cc: "H.J. Lu" , Jeff Law , Cary Coutant , Joe Groff , Binutils , GCC Subject: Re: Preventing preemption of 'protected' symbols in GNU ld 2.26 [aka should we revert the fix for 65248] Message-ID: <20160418144911.GG15088@bubble.grove.modra.org> References: <983472E1-A1BC-4970-9CF9-0138A6BAD16D@apple.com> <6AAD87D2-90F9-4AD7-A195-AC91B76EA6AE@apple.com> <56FB5061.9010303@redhat.com> <20160330143421.GM15812@bubble.grove.modra.org> <571161D0.10601@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-IsSubscribed: yes X-SW-Source: 2016-04/txt/msg00271.txt.bz2 On Mon, Apr 18, 2016 at 11:01:48AM +0200, Richard Biener wrote: > To summarize: there is currently no testcase for a wrong-code issue > because there is no wrong-code issue. That depends entirely on how far you are willing to bend the ELF gABI. Any testcase the takes the address of a protected visibility variable defined in a shared library now can get the wrong answer, since you can argue that any address outside the shared library is wrong according to the gABI. I expect you can also write a testcase using a const protected var in a shared library that ought to segfault on writing to the var from code within the shared library, that now merrily writes to a .dynbss copy. -- Alan Modra Australia Development Lab, IBM