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[23.128.96.18]) by mx.google.com with ESMTP id c16si21312024plo.326.2021.04.20.11.15.01; Tue, 20 Apr 2021 11:15:14 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=HrpX1bto; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 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 S233363AbhDTSOy (ORCPT + 99 others); Tue, 20 Apr 2021 14:14:54 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:47144 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232879AbhDTSOv (ORCPT ); Tue, 20 Apr 2021 14:14:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618942459; 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=xVywtcdWzkrND0c18LWsccBuX85KB1TX7A+WSDqF8ww=; b=HrpX1btowMTUM/VG8Mcff+2Y34Nq9ipIdTt0Vpw9sNFHghTvvYq7oLHyWh8QizOHCGLeF3 4Fxmw/ZaO68uEP2PhE+SZBX0flwH+eQi5ZNPKTljpc/nZcEuF/rDLpKIebRcc/A4azEH3l 4SdchM8djo0rt+ctZxRneGxsaQ7cYos= 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-225-gZ-L1CbPNe6IEJoEIVvKAg-1; Tue, 20 Apr 2021 14:14:17 -0400 X-MC-Unique: gZ-L1CbPNe6IEJoEIVvKAg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 989E9802B56; Tue, 20 Apr 2021 18:14:15 +0000 (UTC) Received: from treble (ovpn-115-229.rdu2.redhat.com [10.10.115.229]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6B9C560C5F; Tue, 20 Apr 2021 18:14:14 +0000 (UTC) Date: Tue, 20 Apr 2021 13:14:12 -0500 From: Josh Poimboeuf To: Sami Tolvanen Cc: x86@kernel.org, Kees Cook , Peter Zijlstra , Nathan Chancellor , Nick Desaulniers , Sedat Dilek , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH 01/15] objtool: Find a destination for jumps beyond the section end Message-ID: <20210420181412.3g5dsyhggxnvif7k@treble> References: <20210416203844.3803177-1-samitolvanen@google.com> <20210416203844.3803177-2-samitolvanen@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210416203844.3803177-2-samitolvanen@google.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 16, 2021 at 01:38:30PM -0700, Sami Tolvanen wrote: > With -ffunction-sections, Clang can generate a jump beyond the end of > a section when the section ends in an unreachable instruction. Why? Can you show an example? -- Josh