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=-5.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 68D45C7618B for ; Fri, 26 Jul 2019 08:20:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 37C4821880 for ; Fri, 26 Jul 2019 08:20:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="Inq66byu"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="jbyk3SjT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725842AbfGZIUd (ORCPT ); Fri, 26 Jul 2019 04:20:33 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:54260 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725815AbfGZIUd (ORCPT ); Fri, 26 Jul 2019 04:20:33 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id D0146602B7; Fri, 26 Jul 2019 08:20:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1564129232; bh=65MgSqdz2cwGluQBrWzKC9i2ys2KqHizYGJpxJMlpW4=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=Inq66byupP164QyjGrEBcnS/t8T29G6gU0pJWkL40Dui5eciw55NAiYmb8beNB95y SNDp5LiUjiefVV1BmvePJwEWieNXSqsdnpYYvgo0/w3ur0Ktv6rAmwfR8k/OU+B8Jh F3Z/Eec7TSqpxJ5YsuYOOihGblVSjkRExL2YBO6s= Received: from [10.79.136.27] (blr-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.18.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: saiprakash.ranjan@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id E0BED602B7; Fri, 26 Jul 2019 08:20:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1564129231; bh=65MgSqdz2cwGluQBrWzKC9i2ys2KqHizYGJpxJMlpW4=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=jbyk3SjTCUTeUB1z3R1MOKw3HJ2oUgr//cWk6BLhbmTq8KRxCRp9MvgtCHtmJ6uuV N8XMHgvcLZULTCiBohg9cCjGjWMSd8flQ0rBdJ+T7DqT8oPH0Dmd+eZhbjgD6mReyr XHLiFuLIo6TtYBWuESeE2cuRqsHNjiuZSyyAzlv0= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org E0BED602B7 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=saiprakash.ranjan@codeaurora.org Subject: Re: [Regression] Missing device nodes for ETR, ETF and STM after CONFIG_UEVENT_HELPER=n To: Greg Kroah-Hartman Cc: Geert Uytterhoeven , Mathieu Poirier , Suzuki K Poulose , Leo Yan , linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20190726070429.GA15714@kroah.com> From: Sai Prakash Ranjan Message-ID: <165028a7-ff12-dd28-cc4c-57a3961dbb40@codeaurora.org> Date: Fri, 26 Jul 2019 13:50:27 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190726070429.GA15714@kroah.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 7/26/2019 12:34 PM, Greg Kroah-Hartman wrote: > On Fri, Jul 26, 2019 at 11:49:19AM +0530, Sai Prakash Ranjan wrote: >> Hi, >> >> When trying to test my coresight patches, I found that etr,etf and stm >> device nodes are missing from /dev. > > I have no idea what those device nodes are. > >> Bisection gives this as the bad commit. >> >> 1be01d4a57142ded23bdb9e0c8d9369e693b26cc is the first bad commit >> commit 1be01d4a57142ded23bdb9e0c8d9369e693b26cc >> Author: Geert Uytterhoeven >> Date: Thu Mar 14 12:13:50 2019 +0100 >> >> driver: base: Disable CONFIG_UEVENT_HELPER by default >> >> Since commit 7934779a69f1184f ("Driver-Core: disable /sbin/hotplug by >> default"), the help text for the /sbin/hotplug fork-bomb says >> "This should not be used today [...] creates a high system load, or >> [...] out-of-memory situations during bootup". The rationale for this >> was that no recent mainstream system used this anymore (in 2010!). >> >> A few years later, the complete uevent helper support was made optional >> in commit 86d56134f1b67d0c ("kobject: Make support for uevent_helper >> optional."). However, if was still left enabled by default, to support >> ancient userland. >> >> Time passed by, and nothing should use this anymore, so it can be >> disabled by default. >> >> Signed-off-by: Geert Uytterhoeven >> Signed-off-by: Greg Kroah-Hartman >> >> drivers/base/Kconfig | 1 - >> 1 file changed, 1 deletion(-) >> >> >> Any idea on this? > > That means that who ever created those device nodes is relying on udev > to do this, and is not doing the correct thing within the kernel and > using devtmpfs. > > Any pointers to where in the kernel those devices are trying to be > created? > Somewhere in drivers/hwtracing/coresight/* probably. I am not sure, Mathieu/Suzuki would be able to point you to the exact code. Also just to add on some more details, I am using *initramfs* Thanks, Sai -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation