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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,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 21D6AC43381 for ; Sat, 30 Mar 2019 00:54:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E703B21906 for ; Sat, 30 Mar 2019 00:54:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553907258; bh=Z1Q8D7zIjR/mIcuCnwXgI9rdto7h8zya3aEs688B2N4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jof/XDe55IhvByTRustB+mOFe5UELlNHNuUaayU86S4HdUZMSRKbXaYgASCEfmyxJ vYmiO5gKFswTzQHWHXKLOXFOeBdYC30VcGK3LeNRgw/RChLkl0YzaoNEWUSqlMJXOb xcGvW1jKqA1Ck0dgSuSRmWyMnxLO0Zgcr5ksx+fA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731481AbfC3AyR (ORCPT ); Fri, 29 Mar 2019 20:54:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:33120 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731473AbfC3AyQ (ORCPT ); Fri, 29 Mar 2019 20:54:16 -0400 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 C0BEE218AC; Sat, 30 Mar 2019 00:54:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1553907255; bh=Z1Q8D7zIjR/mIcuCnwXgI9rdto7h8zya3aEs688B2N4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OoeKosLNzrzjIygL2eXtpOyX46O3qfVlyPIYYcO0u9y5BU+yXn3O7TmHTIw9g2yO5 Mzly/ir+ikhUVaI0Wjmta8OccAFbU07CoEvkYeqzI2yxpM6DY9or/2uaDDn0ODzD0D r58UbPzHo7dShrn1R2YvwJY/Tft9Ol6ayGMOMEb4= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jiada Wang , "Rafael J . Wysocki" , Sasha Levin , linux-pm@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 39/52] PM / Domains: Avoid a potential deadlock Date: Fri, 29 Mar 2019 20:52:46 -0400 Message-Id: <20190330005301.26868-39-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190330005301.26868-1-sashal@kernel.org> References: <20190330005301.26868-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jiada Wang [ Upstream commit 2071ac985d37efe496782c34318dbead93beb02f ] Lockdep warns that prepare_lock and genpd->mlock can cause a deadlock the deadlock scenario is like following: First thread is probing cs2000 cs2000_probe() clk_register() __clk_core_init() clk_prepare_lock() ----> acquires prepare_lock cs2000_recalc_rate() i2c_smbus_read_byte_data() rcar_i2c_master_xfer() dma_request_chan() rcar_dmac_of_xlate() rcar_dmac_alloc_chan_resources() pm_runtime_get_sync() __pm_runtime_resume() rpm_resume() rpm_callback() genpd_runtime_resume() ----> acquires genpd->mlock Second thread is attaching any device to the same PM domain genpd_add_device() genpd_lock() ----> acquires genpd->mlock cpg_mssr_attach_dev() of_clk_get_from_provider() __of_clk_get_from_provider() __clk_create_clk() clk_prepare_lock() ----> acquires prepare_lock Since currently no PM provider access genpd's critical section in .attach_dev, and .detach_dev callbacks, so there is no need to protect these two callbacks with genpd->mlock. This patch avoids a potential deadlock by moving out .attach_dev and .detach_dev from genpd->mlock, so that genpd->mlock won't be held when prepare_lock is acquired in .attach_dev and .detach_dev Signed-off-by: Jiada Wang Reviewed-by: Ulf Hansson Tested-by: Geert Uytterhoeven Reviewed-by: Geert Uytterhoeven Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- drivers/base/power/domain.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index 4b5714199490..bf5be0bfaf77 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -1388,12 +1388,12 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, if (IS_ERR(gpd_data)) return PTR_ERR(gpd_data); - genpd_lock(genpd); - ret = genpd->attach_dev ? genpd->attach_dev(genpd, dev) : 0; if (ret) goto out; + genpd_lock(genpd); + dev_pm_domain_set(dev, &genpd->domain); genpd->device_count++; @@ -1401,9 +1401,8 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev, list_add_tail(&gpd_data->base.list_node, &genpd->dev_list); - out: genpd_unlock(genpd); - + out: if (ret) genpd_free_dev_data(dev, gpd_data); else @@ -1452,15 +1451,15 @@ static int genpd_remove_device(struct generic_pm_domain *genpd, genpd->device_count--; genpd->max_off_time_changed = true; - if (genpd->detach_dev) - genpd->detach_dev(genpd, dev); - dev_pm_domain_set(dev, NULL); list_del_init(&pdd->list_node); genpd_unlock(genpd); + if (genpd->detach_dev) + genpd->detach_dev(genpd, dev); + genpd_free_dev_data(dev, gpd_data); return 0; -- 2.19.1