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=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 00EB5C76191 for ; Fri, 26 Jul 2019 11:43:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4F5622BEF for ; Fri, 26 Jul 2019 11:43:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564141410; bh=5yhEY4/CW3iFSx6x2N72Exb83PWgWW4WYbcupxxH+EQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=pxwB3isgG5Hvd2PNCuZVdRKLuH/3xNn/hSdLBpxepJrn3judauCMIW8i9jgFjX2i5 tG+8a9IJD9FJCXGwBpgqoeIm1Rg0vRDuiB3D3jXZxOQT1UnP+2JB7MLxsAJaCOhdM7 knJh9Fs2gWfmoSw60PGmrqfzpCiNmIFTGYlTdxcQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726138AbfGZLna (ORCPT ); Fri, 26 Jul 2019 07:43:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:44720 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725903AbfGZLn3 (ORCPT ); Fri, 26 Jul 2019 07:43:29 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 69DED229F3; Fri, 26 Jul 2019 11:43:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564141408; bh=5yhEY4/CW3iFSx6x2N72Exb83PWgWW4WYbcupxxH+EQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=2agoaOv3lpVGYhSQxrkRuDOARn2KEXJcqmDa7xybgtHiM6/IJNjdpLnyRHt7Aubtc X8i7PeL0fMglVJ+kGD7HlNNxki0h00bW92TbkewMZwyidxTXpksfKgvJIVrarwrs/f 4bwd5fiplYiGBI4MZPkaodlW/in25rCAMv7VrmOs= Date: Fri, 26 Jul 2019 13:43:25 +0200 From: Greg Kroah-Hartman To: Thomas Petazzoni Cc: Sai Prakash Ranjan , Geert Uytterhoeven , Mathieu Poirier , Suzuki K Poulose , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Leo Yan , linux-arm-kernel@lists.infradead.org Subject: Re: [Regression] Missing device nodes for ETR, ETF and STM after CONFIG_UEVENT_HELPER=n Message-ID: <20190726114325.GA18727@kroah.com> References: <20190726070429.GA15714@kroah.com> <165028a7-ff12-dd28-cc4c-57a3961dbb40@codeaurora.org> <20190726084127.GA28470@kroah.com> <097942a1-6914-2542-450f-65a6147dc7aa@codeaurora.org> <6d48f996-6297-dc69-250b-790be6d2670c@codeaurora.org> <20190726101925.GA22476@kroah.com> <20190726133316.688a43d8@windsurf> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190726133316.688a43d8@windsurf> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 26, 2019 at 01:33:16PM +0200, Thomas Petazzoni wrote: > Hello, > > On Fri, 26 Jul 2019 12:19:25 +0200 > Greg Kroah-Hartman wrote: > > > > This somehow is not mounting etr, etf, stm devices when uevent-helper is > > > disabled. Anyways as Suzuki mentioned, using devtmpfs does fix the issue. > > > > Last I looked (many years ago) mdev requires uevent-helper in order for > > it to work. I recommend that if you rely on mdev to keep that option > > enabled, or to just use devtmpfs and udev :) > > Since Busybox 1.31.0, mdev has gained a daemon mode. In this mode, mdev > runs in the background, and receives uevent through a netlink socket. > So there's been some changes in how Busybox mdev works in recent times. Ideally mdev should switch to what udev did many many years ago and not do any device node creations and just leave all of that up to devtmpfs. Then it can just stick to any symlinks and any specific owner:group permissions that might be wanted separate from the default ones the kernel provides. Makes things much simpler and should save a lot of userspace code, making mdev even smaller. thanks, greg k-h