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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 82F39C433F5 for ; Wed, 6 Apr 2022 14:49:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235013AbiDFOvT (ORCPT ); Wed, 6 Apr 2022 10:51:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33192 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235334AbiDFOuo (ORCPT ); Wed, 6 Apr 2022 10:50:44 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2212B5E9860; Wed, 6 Apr 2022 04:23:30 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 767D8B82014; Wed, 6 Apr 2022 11:23:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A2FBC385A3; Wed, 6 Apr 2022 11:23:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1649244208; bh=SjcaJJhx4BXe6tnaJctHdMtT1mA4dYXjywpMRbdjPeA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=N7tchrJdtzp4jeVjHtb9aLdDQoEL3gt3zjKdL4UzSzCFF6Xg1mW9TB0tAtjFWMIS5 IhpmUGk3sd9JLznarD+6dgCgpH7XT7sVQdm4RhxCGAhJH+16lwkCgGybxONSSm8CJb ckrFdnTXxqUt7zLrcesjQ84WLYHk5LNKM02HG2k8SAfob4vwZQXmW2sOqE4jvprXR3 tWPBPCRUhaCU2jW5ALDmWFhWMq+rCxzWci8pH90PnV+Ewr+aRRMlYvisbpWrKO8NiL rPTbLAfl954xdZM5ROBWBtHjd1Bg+qAatC8RsixNgzPhN7vTv7Qc3l2N2QU5sLwRkG 6n/g3YaDEFlQw== Date: Wed, 6 Apr 2022 07:23:26 -0400 From: Sasha Levin To: Ard Biesheuvel Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, stable@vger.kernel.org, "Steven Rostedt (Google)" Subject: Re: [PATCH 5.15 746/913] ARM: ftrace: avoid redundant loads or clobbering IP Message-ID: References: <20220405070339.801210740@linuxfoundation.org> <20220405070402.195698649@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 05, 2022 at 12:01:19PM +0200, Ard Biesheuvel wrote: >On Tue, 5 Apr 2022 at 11:54, Greg Kroah-Hartman > wrote: >> >> From: Ard Biesheuvel >> >> [ Upstream commit d11967870815b5ab89843980e35aab616c97c463 ] >> >> Tweak the ftrace return paths to avoid redundant loads of SP, as well as >> unnecessary clobbering of IP. >> >> This also fixes the inconsistency of using MOV to perform a function >> return, which is sub-optimal on recent micro-architectures but more >> importantly, does not perform an interworking return, unlike compiler >> generated function returns in Thumb2 builds. >> >> Let's fix this by popping PC from the stack like most ordinary code >> does. >> >> Signed-off-by: Ard Biesheuvel >> Reviewed-by: Steven Rostedt (Google) >> Signed-off-by: Sasha Levin > >Please drop all the 32-bit ARM patches authored by me from the stable >queues except the ones that have fixes tags. These are highly likely I can drop you from future selections as well. >to cause an explosion of regressions, and they should have never been >selected, as I don't remember anyone proposing these for stable. They were proposed by the bot last week (https://lore.kernel.org/lkml/20220330115005.1671090-22-sashal@kernel.org/). -- Thanks, Sasha