From patchwork Fri Jun 3 11:31:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 578596 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 A5D2DC433EF for ; Fri, 3 Jun 2022 11:32:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244047AbiFCLcq (ORCPT ); Fri, 3 Jun 2022 07:32:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54894 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244040AbiFCLco (ORCPT ); Fri, 3 Jun 2022 07:32:44 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8DAAA657A; Fri, 3 Jun 2022 04:32:43 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 2BC446121E; Fri, 3 Jun 2022 11:32:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6390C385A9; Fri, 3 Jun 2022 11:32:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1654255962; bh=myYHQBAtxsgh3YAl4G2/KmIJpUKMkCYSq4SI0B3ycQw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1dPEkQLNIIwfjjXcy9eaC9MPBqHbOA0iF72mdp7QtXKOnt/+cNr7cpnuKJJGunDjk 0kjYMvnbFLhhnarwdm7cq64+BmeoKDUSlWH+vsLhvTUh7W5t76CqwQXgcdWpj5sclb F9QHtB9MBJpMAcWWsly7ooef69b1lTQS9xi10E20= From: Greg Kroah-Hartman To: Linus Torvalds , Andrew Morton Cc: linux-kernel@vger.kernel.org, Stephen Rothwell , Saravana Kannan , John Stultz , "David S. Miller" , Alexey Kuznetsov , Hideaki YOSHIFUJI , Jakub Kicinski , "Rafael J . Wysocki" , Rob Herring , Geert Uytterhoeven , Yoshihiro Shimoda , Robin Murphy , Andy Shevchenko , Sudeep Holla , Andy Shevchenko , Naresh Kamboju , Basil Eljuse , Ferry Toth , Arnd Bergmann , Anders Roxell , linux-pm@vger.kernel.org, Nathan Chancellor , Sebastian Andrzej Siewior , Geert Uytterhoeven , Greg Kroah-Hartman Subject: [PATCH 1/2] driver core: Fix wait_for_device_probe() & deferred_probe_timeout interaction Date: Fri, 3 Jun 2022 13:31:37 +0200 Message-Id: <20220603113138.2689444-1-gregkh@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: References: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3968; i=gregkh@linuxfoundation.org; h=from:subject; bh=MnYHk+TvRioyuCp9YPlGhGUqIO1D63k02GXidwo/63o=; b=owGbwMvMwCRo6H6F97bub03G02pJDEkzP0q1eJW4MB4LyH/2fDevn8ub8wn3l60WiBcVfzHtPlOO +rxnHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjCR1a8YFjTlF1+f8YiZgYNly+EcL+ 3IL1WPMhhms1x10duet+p29qmIfknry9zdavJnAQ== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Saravana Kannan Mounting NFS rootfs was timing out when deferred_probe_timeout was non-zero [1]. This was because ip_auto_config() initcall times out waiting for the network interfaces to show up when deferred_probe_timeout was non-zero. While ip_auto_config() calls wait_for_device_probe() to make sure any currently running deferred probe work or asynchronous probe finishes, that wasn't sufficient to account for devices being deferred until deferred_probe_timeout. Commit 35a672363ab3 ("driver core: Ensure wait_for_device_probe() waits until the deferred_probe_timeout fires") tried to fix that by making sure wait_for_device_probe() waits for deferred_probe_timeout to expire before returning. However, if wait_for_device_probe() is called from the kernel_init() context: - Before deferred_probe_initcall() [2], it causes the boot process to hang due to a deadlock. - After deferred_probe_initcall() [3], it blocks kernel_init() from continuing till deferred_probe_timeout expires and beats the point of deferred_probe_timeout that's trying to wait for userspace to load modules. Neither of this is good. So revert the changes to wait_for_device_probe(). [1] - https://lore.kernel.org/lkml/TYAPR01MB45443DF63B9EF29054F7C41FD8C60@TYAPR01MB4544.jpnprd01.prod.outlook.com/ [2] - https://lore.kernel.org/lkml/YowHNo4sBjr9ijZr@dev-arch.thelio-3990X/ [3] - https://lore.kernel.org/lkml/Yo3WvGnNk3LvLb7R@linutronix.de/ Fixes: 35a672363ab3 ("driver core: Ensure wait_for_device_probe() waits until the deferred_probe_timeout fires") Cc: John Stultz Cc: "David S. Miller" Cc: Alexey Kuznetsov Cc: Hideaki YOSHIFUJI Cc: Jakub Kicinski Cc: Rafael J. Wysocki Cc: Rob Herring Cc: Geert Uytterhoeven Cc: Yoshihiro Shimoda Cc: Robin Murphy Cc: Andy Shevchenko Cc: Sudeep Holla Cc: Andy Shevchenko Cc: Naresh Kamboju Cc: Basil Eljuse Cc: Ferry Toth Cc: Arnd Bergmann Cc: Anders Roxell Cc: linux-pm@vger.kernel.org Reported-by: Nathan Chancellor Reported-by: Sebastian Andrzej Siewior Tested-by: Geert Uytterhoeven Acked-by: John Stultz Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20220526034609.480766-2-saravanak@google.com Signed-off-by: Greg Kroah-Hartman Reviewed-by: Rafael J. Wysocki --- drivers/base/dd.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 2fc8507f59ee..91f63cd33b12 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -263,7 +263,6 @@ int driver_deferred_probe_timeout; #endif EXPORT_SYMBOL_GPL(driver_deferred_probe_timeout); -static DECLARE_WAIT_QUEUE_HEAD(probe_timeout_waitqueue); static int __init deferred_probe_timeout_setup(char *str) { @@ -318,7 +317,6 @@ static void deferred_probe_timeout_work_func(struct work_struct *work) list_for_each_entry(p, &deferred_probe_pending_list, deferred_probe) dev_info(p->device, "deferred probe pending\n"); mutex_unlock(&deferred_probe_mutex); - wake_up_all(&probe_timeout_waitqueue); } static DECLARE_DELAYED_WORK(deferred_probe_timeout_work, deferred_probe_timeout_work_func); @@ -736,9 +734,6 @@ int driver_probe_done(void) */ void wait_for_device_probe(void) { - /* wait for probe timeout */ - wait_event(probe_timeout_waitqueue, !driver_deferred_probe_timeout); - /* wait for the deferred probe workqueue to finish */ flush_work(&deferred_probe_work);