From patchwork Tue Dec 22 13:13:01 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Kurtz X-Patchwork-Id: 7904541 X-Patchwork-Delegate: rjw@sisk.pl Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id D18819F1AF for ; Tue, 22 Dec 2015 13:15:02 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CC80F20502 for ; Tue, 22 Dec 2015 13:15:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6621A204DE for ; Tue, 22 Dec 2015 13:14:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752889AbbLVNOe (ORCPT ); Tue, 22 Dec 2015 08:14:34 -0500 Received: from mail-pa0-f44.google.com ([209.85.220.44]:35379 "EHLO mail-pa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752078AbbLVNOd (ORCPT ); Tue, 22 Dec 2015 08:14:33 -0500 Received: by mail-pa0-f44.google.com with SMTP id jx14so89545831pad.2 for ; Tue, 22 Dec 2015 05:14:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id; bh=aYO/duBWNbyPQ/AVPy3yjiA/XJsTuv4FSqM7bMkJkD4=; b=TM1f3EYndCRmivqh1/zSwkWF26+eKp1J7JXIQkpS2LXJKNEmoYRU6BVfqCpGO7suma pMUHkUJIGnnD1PnYh/Z96V1/SMYVU5NeS319I1BxgEE12ZAPB/pEfl2KyR3IVNoX0yt2 +ovMySyevfWBcGV7JTu5741Ci76quL6H/MwbI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=aYO/duBWNbyPQ/AVPy3yjiA/XJsTuv4FSqM7bMkJkD4=; b=TWZoHnH/9oAleYEr8GjlMI6aZ4nnZ8+TM3lKmdMcj5m7z7d2ph9B/PNUyXzpiG+kc1 tdBGR+e4fBGzQKvzjX93j8D09aM05oxmWKMMwprDVn4a9/S3+plnH4SaNrBpmylaxhDA bYv898A1KeXqtPE2NzyX3NMTVJhpgVs9psciNDqG5a2wY/1BnVGPAPMMMXJPUz+guxjW PS2s5oUJhGlv5eiYjbwrt4XqRZf9ATZv+/5WTU7pQkahtNIu6iJYHjbyMEmS9fU67PI0 2pY353bSDzjh8pXIOv8V0GCd05+H+7BpUXX4kpVNwqhBZ7OCnU7QLJLmXa1gKYAFVdJ+ EaBw== X-Gm-Message-State: ALoCoQlVJ17/6ezWv+h23VFT1BTYLsUUn4gCjEqGl0MH3JRGG7j4tpZ7CsC9sNxyf6nJsVuW9uQPizQAzwPD6+6i4c5r06q56A== X-Received: by 10.66.139.131 with SMTP id qy3mr35680773pab.71.1450790072609; Tue, 22 Dec 2015 05:14:32 -0800 (PST) Received: from djkurtz1.tpe.corp.google.com ([172.30.210.4]) by smtp.gmail.com with ESMTPSA id a15sm20696298pfj.31.2015.12.22.05.14.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 22 Dec 2015 05:14:30 -0800 (PST) From: Daniel Kurtz Cc: jcliang@chromium.org, drinkcat@chromium.org, ville.syrjala@linux.intel.com, Daniel Kurtz , stable@vger.kernel.org, "Rafael J. Wysocki" , Kevin Hilman , Ulf Hansson , Pavel Machek , Len Brown , Greg Kroah-Hartman , linux-pm@vger.kernel.org (open list:GENERIC PM DOMAINS), linux-kernel@vger.kernel.org (open list) Subject: [PATCH] PM / Domains: Release mutex when powering on master domain Date: Tue, 22 Dec 2015 21:13:01 +0800 Message-Id: <1450789981-29877-1-git-send-email-djkurtz@chromium.org> X-Mailer: git-send-email 2.6.0.rc2.230.g3dd15c0 To: unlisted-recipients:; (no To-header on input) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Commit ba2bbfbf6307 (PM / Domains: Remove intermediate states from the power off sequence) removed the mutex_unlock()/_lock() around powering on a genpd's master domain in __genpd_poweron(). Since all genpd's share a mutex lockdep class, this causes a "possible recursive locking detected" lockdep warning on boot when trying to power on a genpd slave domain: [ 1.893137] ============================================= [ 1.893139] [ INFO: possible recursive locking detected ] [ 1.893143] 3.18.0 #531 Not tainted [ 1.893145] --------------------------------------------- [ 1.893148] kworker/u8:4/113 is trying to acquire lock: [ 1.893167] (&genpd->lock){+.+...}, at: [] genpd_poweron+0x30/0x70 [ 1.893169] [ 1.893169] but task is already holding lock: [ 1.893179] (&genpd->lock){+.+...}, at: [] genpd_poweron+0x30/0x70 [ 1.893182] [ 1.893182] other info that might help us debug this: [ 1.893184] Possible unsafe locking scenario: [ 1.893184] [ 1.893185] CPU0 [ 1.893187] ---- [ 1.893191] lock(&genpd->lock); [ 1.893195] lock(&genpd->lock); [ 1.893196] [ 1.893196] *** DEADLOCK *** [ 1.893196] [ 1.893198] May be due to missing lock nesting notation [ 1.893198] [ 1.893201] 4 locks held by kworker/u8:4/113: [ 1.893217] #0: ("%s""deferwq"){++++.+}, at: [] process_one_work+0x1f8/0x50c [ 1.893229] #1: (deferred_probe_work){+.+.+.}, at: [] process_one_work+0x1f8/0x50c [ 1.893241] #2: (&dev->mutex){......}, at: [] __device_attach+0x40/0x12c [ 1.893251] #3: (&genpd->lock){+.+...}, at: [] genpd_poweron+0x30/0x70 [ 1.893253] [ 1.893253] stack backtrace: [ 1.893259] CPU: 2 PID: 113 Comm: kworker/u8:4 Not tainted 3.18.0 #531 [ 1.893269] Workqueue: deferwq deferred_probe_work_func [ 1.893271] Call trace: [ 1.893295] [] __lock_acquire+0x68c/0x19a8 [ 1.893299] [] lock_acquire+0x128/0x164 [ 1.893304] [] mutex_lock_nested+0x90/0x3b4 [ 1.893308] [] genpd_poweron+0x2c/0x70 [ 1.893312] [] __genpd_poweron.part.14+0x54/0xcc [ 1.893316] [] genpd_poweron+0x4c/0x70 [ 1.893321] [] genpd_dev_pm_attach+0x160/0x19c [ 1.893326] [] dev_pm_domain_attach+0x1c/0x2c ... Fix this by releasing the slaves mutex before acquiring the master's, which restores the old behavior. Cc: stable@vger.kernel.org Fixes: 5d837eef7b99 ("PM / Domains: Remove intermediate states from the power off sequence") Signed-off-by: Daniel Kurtz Acked-by: Kevin Hilman --- drivers/base/power/domain.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index 65f50ec..56fa335 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -196,7 +196,12 @@ static int __genpd_poweron(struct generic_pm_domain *genpd) list_for_each_entry(link, &genpd->slave_links, slave_node) { genpd_sd_counter_inc(link->master); + mutex_unlock(&genpd->lock); + ret = genpd_poweron(link->master); + + mutex_lock(&genpd->lock); + if (ret) { genpd_sd_counter_dec(link->master); goto err;