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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 DD79BC33CAF for ; Thu, 16 Jan 2020 17:24:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 38C44246B2 for ; Thu, 16 Jan 2020 17:24:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579195474; bh=E9/Ww4y9YdhwMmYXt1K5PyyFf1xMnzDhgJe1u5TnmNc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1DqDmvGIPDnYN5ziQBLWy+CbVqCmEu5OGKeaaZBSx+yFq8rvdI1LvL7ePeRdlZkdR i1v1UK/Ub7681GG0hxDWjdRM/I3NZfbfokDr6hh2h4fnwvlpYqsb93Sy6Vi8cVT5/N cRdgF8LIDs9tCXcWa3tZsVslU+Erzlg+gKsCPovg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391235AbgAPRYd (ORCPT ); Thu, 16 Jan 2020 12:24:33 -0500 Received: from mail.kernel.org ([198.145.29.99]:58942 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391658AbgAPRY1 (ORCPT ); Thu, 16 Jan 2020 12:24:27 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 55A41246A6; Thu, 16 Jan 2020 17:24:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579195466; bh=E9/Ww4y9YdhwMmYXt1K5PyyFf1xMnzDhgJe1u5TnmNc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d3X+mpznovlpSqXyDlIX7PqbrDlAJW7ZGwF96H4yU8ufABeB1zbwB8R97mMomPMFE dDHc7r5sFOa6F9y3zc63FQ35gA5Iw9pXxyEozuC9akk9+8xTqPMUKkW1DE+3ATAb+J RS71I7P0cUArUrgrE9OSSvthB1NxTM3RxIyCRfhs= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: "Rafael J. Wysocki" , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH AUTOSEL 4.14 074/371] driver core: Do not resume suppliers under device_links_write_lock() Date: Thu, 16 Jan 2020 12:19:06 -0500 Message-Id: <20200116172403.18149-17-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200116172403.18149-1-sashal@kernel.org> References: <20200116172403.18149-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Rafael J. Wysocki" [ Upstream commit 5db25c9eb893df8f6b93c1d97b8006d768e1b6f5 ] It is incorrect to call pm_runtime_get_sync() under device_links_write_lock(), because it may end up trying to take device_links_read_lock() while resuming the target device and that will deadlock in the non-SRCU case, so avoid that by resuming the supplier device in device_link_add() before calling device_links_write_lock(). Fixes: 21d5c57b3726 ("PM / runtime: Use device links") Fixes: baa8809f6097 ("PM / runtime: Optimize the use of device links") Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/base/core.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 2b0a1054535c..93c2fc58013e 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -180,11 +180,20 @@ struct device_link *device_link_add(struct device *consumer, struct device *supplier, u32 flags) { struct device_link *link; + bool rpm_put_supplier = false; if (!consumer || !supplier || ((flags & DL_FLAG_STATELESS) && (flags & DL_FLAG_AUTOREMOVE))) return NULL; + if (flags & DL_FLAG_PM_RUNTIME && flags & DL_FLAG_RPM_ACTIVE) { + if (pm_runtime_get_sync(supplier) < 0) { + pm_runtime_put_noidle(supplier); + return NULL; + } + rpm_put_supplier = true; + } + device_links_write_lock(); device_pm_lock(); @@ -209,13 +218,8 @@ struct device_link *device_link_add(struct device *consumer, if (flags & DL_FLAG_PM_RUNTIME) { if (flags & DL_FLAG_RPM_ACTIVE) { - if (pm_runtime_get_sync(supplier) < 0) { - pm_runtime_put_noidle(supplier); - kfree(link); - link = NULL; - goto out; - } link->rpm_active = true; + rpm_put_supplier = false; } pm_runtime_new_link(consumer); /* @@ -286,6 +290,10 @@ struct device_link *device_link_add(struct device *consumer, out: device_pm_unlock(); device_links_write_unlock(); + + if (rpm_put_supplier) + pm_runtime_put(supplier); + return link; } EXPORT_SYMBOL_GPL(device_link_add); -- 2.20.1