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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 32F6BC433EF for ; Fri, 24 Sep 2021 13:01:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1919B61263 for ; Fri, 24 Sep 2021 13:01:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344849AbhIXNDR (ORCPT ); Fri, 24 Sep 2021 09:03:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:57332 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345431AbhIXNBV (ORCPT ); Fri, 24 Sep 2021 09:01:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8FA3861269; Fri, 24 Sep 2021 12:54:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1632488052; bh=KWGTorvk9vSsJ6GBOeej2BLeMw45GFlJy5WHEo2IMHs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xPRnld5okXsTpqxJkaVplwma4xcsQWbNrJO9uYhiUwoqFuqXm2Rz4wEw9jlkueT9B oaSakONY50gAx+LcqppeJi5VV7psMvTiqR3Md6SGadcO1WESTBu+uWZyg1ZwlrQXuK A5qoHxJyH+ikAB1fXWJrTh0h8mmM/iHf5Cf0tRX4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rasmus Villemoes , Alexander Egorenkov , Bruno Goncalves , Heiner Kallweit , Luis Chamberlain , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 5.14 037/100] init: move usermodehelper_enable() to populate_rootfs() Date: Fri, 24 Sep 2021 14:43:46 +0200 Message-Id: <20210924124342.703209208@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20210924124341.214446495@linuxfoundation.org> References: <20210924124341.214446495@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Rasmus Villemoes [ Upstream commit b234ed6d629420827e2839c8c8935be85a0867fd ] Currently, usermodehelper is enabled right before PID1 starts going through the initcalls. However, any call of a usermodehelper from a pure_, core_, postcore_, arch_, subsys_ or fs_ initcall is futile, as there is no filesystem contents yet. Up until commit e7cb072eb988 ("init/initramfs.c: do unpacking asynchronously"), such calls, whether via some request_module(), a legacy uevent "/sbin/hotplug" notification or something else, would just fail silently with (presumably) -ENOENT from kernel_execve(). However, that commit introduced the wait_for_initramfs() synchronization hook which must be called from the usermodehelper exec path right before the kernel_execve, in order that request_module() et al done from *after* rootfs_initcall() time (i.e. device_ and late_ initcalls) would continue to find a populated initramfs as they used to. Any call of wait_for_initramfs() done before the unpacking has been scheduled (i.e. before rootfs_initcall time) must just return immediately [and let the caller find an empty file system] in order not to deadlock the machine. I mistakenly thought, and my limited testing confirmed, that there were no such calls, so I added a pr_warn_once() in wait_for_initramfs(). It turns out that one can indeed hit request_module() as well as kobject_uevent_env() during those early init calls, leading to a user-visible warning in the kernel log emitted consistently for certain configurations. We could just remove the pr_warn_once(), but I think it's better to postpone enabling the usermodehelper framework until there is at least some chance of finding the executable. That is also a little more efficient in that a lot of work done in umh.c will be elided. However, it does change the error seen by those early callers from -ENOENT to -EBUSY, so there is a risk of a regression if any caller care about the exact error value. Link: https://lkml.kernel.org/r/20210728134638.329060-1-linux@rasmusvillemoes.dk Fixes: e7cb072eb988 ("init/initramfs.c: do unpacking asynchronously") Signed-off-by: Rasmus Villemoes Reported-by: Alexander Egorenkov Reported-by: Bruno Goncalves Reported-by: Heiner Kallweit Cc: Luis Chamberlain Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- init/initramfs.c | 2 ++ init/main.c | 1 - init/noinitramfs.c | 2 ++ 3 files changed, 4 insertions(+), 1 deletion(-) diff --git a/init/initramfs.c b/init/initramfs.c index af27abc59643..a842c0544745 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -15,6 +15,7 @@ #include #include #include +#include static ssize_t __init xwrite(struct file *file, const char *p, size_t count, loff_t *pos) @@ -727,6 +728,7 @@ static int __init populate_rootfs(void) { initramfs_cookie = async_schedule_domain(do_populate_rootfs, NULL, &initramfs_domain); + usermodehelper_enable(); if (!initramfs_async) wait_for_initramfs(); return 0; diff --git a/init/main.c b/init/main.c index 8d97aba78c3a..90733a916791 100644 --- a/init/main.c +++ b/init/main.c @@ -1392,7 +1392,6 @@ static void __init do_basic_setup(void) driver_init(); init_irq_proc(); do_ctors(); - usermodehelper_enable(); do_initcalls(); } diff --git a/init/noinitramfs.c b/init/noinitramfs.c index 3d62b07f3bb9..d1d26b93d25c 100644 --- a/init/noinitramfs.c +++ b/init/noinitramfs.c @@ -10,6 +10,7 @@ #include #include #include +#include /* * Create a simple rootfs that is similar to the default initramfs @@ -18,6 +19,7 @@ static int __init default_rootfs(void) { int err; + usermodehelper_enable(); err = init_mkdir("/dev", 0755); if (err < 0) goto out; -- 2.33.0