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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 C0B81C76190 for ; Tue, 23 Jul 2019 01:31:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A2DCB21BF6 for ; Tue, 23 Jul 2019 01:31:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387774AbfGWBbI (ORCPT ); Mon, 22 Jul 2019 21:31:08 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:52638 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728108AbfGWBbI (ORCPT ); Mon, 22 Jul 2019 21:31:08 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id EF0E115305EB4; Mon, 22 Jul 2019 18:31:07 -0700 (PDT) Date: Mon, 22 Jul 2019 18:31:07 -0700 (PDT) Message-Id: <20190722.183107.298639131733640783.davem@davemloft.net> To: arnd@arndb.de Cc: dhowells@redhat.com, keescook@chromium.org, linux-afs@lists.infradead.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH net-next] rxrpc: shut up -Wframe-larger-than= warnings From: David Miller In-Reply-To: <20190722145828.1156135-1-arnd@arndb.de> References: <20190722145828.1156135-1-arnd@arndb.de> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 22 Jul 2019 18:31:08 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Arnd Bergmann Date: Mon, 22 Jul 2019 16:58:12 +0200 > rxkad sometimes triggers a warning about oversized stack frames > when building with clang for a 32-bit architecture: > > net/rxrpc/rxkad.c:243:12: error: stack frame size of 1088 bytes in function 'rxkad_secure_packet' [-Werror,-Wframe-larger-than=] > net/rxrpc/rxkad.c:501:12: error: stack frame size of 1088 bytes in function 'rxkad_verify_packet' [-Werror,-Wframe-larger-than=] > > The problem is the combination of SYNC_SKCIPHER_REQUEST_ON_STACK() > in rxkad_verify_packet()/rxkad_secure_packet() with the relatively > large scatterlist in rxkad_verify_packet_1()/rxkad_secure_packet_encrypt(). > > The warning does not show up when using gcc, which does not inline > the functions as aggressively, but the problem is still the same. > > Marking the inner functions as 'noinline_for_stack' makes clang > behave the same way as gcc and avoids the warning. > This may not be ideal as it leaves the underlying problem > unchanged. If we want to actually reduce the stack usage here, > the skcipher_request and scatterlist objects need to be moved > off the stack. > > Signed-off-by: Arnd Bergmann David H., I assume you will take this into your tree.