From patchwork Mon Jun 13 10:10:10 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: 581894 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 34F5FCCA47B for ; Mon, 13 Jun 2022 13:11:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240886AbiFMNLZ (ORCPT ); Mon, 13 Jun 2022 09:11:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357627AbiFMNGY (ORCPT ); Mon, 13 Jun 2022 09:06:24 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65D6636B71; Mon, 13 Jun 2022 04:18:20 -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 18F27B80D31; Mon, 13 Jun 2022 11:18:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 583D5C3411C; Mon, 13 Jun 2022 11:18:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655119083; bh=4NUSCTNVCAPRaqG0IRwk7W4XUU7ZquBP4nhbrj5/Yas=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rkMXNbWxZnA6hHcRmoTqAeH473O+RmpFQ4JkuXKKSLgu1CcMAww4ubJlKzsXc5EZt sWvpLN70pd2TvYgVogxLgIn+RHWKru2ZXV3q/d68HcYzncT3Ulfv55uOi92SPmZiMp 286Y5JEevFJcHIS9/+j3+uOx5NSKhzvGHO8haVXI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, John Stultz , "David S. Miller" , Alexey Kuznetsov , Hideaki YOSHIFUJI , Jakub Kicinski , 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 , Saravana Kannan , "Rafael J. Wysocki" , Linus Torvalds , Sasha Levin Subject: [PATCH 5.15 108/247] driver core: Fix wait_for_device_probe() & deferred_probe_timeout interaction Date: Mon, 13 Jun 2022 12:10:10 +0200 Message-Id: <20220613094926.235396426@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094922.843438024@linuxfoundation.org> References: <20220613094922.843438024@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Saravana Kannan [ Upstream commit 5ee76c256e928455212ab759c51d198fedbe7523 ] 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: 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 Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- drivers/base/dd.c | 5 ----- 1 file changed, 5 deletions(-) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index a480004b9897..76ded601d0c1 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -257,7 +257,6 @@ DEFINE_SHOW_ATTRIBUTE(deferred_devs); int driver_deferred_probe_timeout; EXPORT_SYMBOL_GPL(driver_deferred_probe_timeout); -static DECLARE_WAIT_QUEUE_HEAD(probe_timeout_waitqueue); static int __init deferred_probe_timeout_setup(char *str) { @@ -312,7 +311,6 @@ 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); @@ -719,9 +717,6 @@ 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);