From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933242AbcECA0l (ORCPT ); Mon, 2 May 2016 20:26:41 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:60233 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933006AbcECA0i (ORCPT ); Mon, 2 May 2016 20:26:38 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mark Brown , Arnd Bergmann , Thierry Reding , Guenter Roeck Subject: [PATCH 4.4 115/163] regulator: core: Fix nested locking of supplies Date: Mon, 2 May 2016 17:12:23 -0700 Message-Id: <20160503000512.280699993@linuxfoundation.org> X-Mailer: git-send-email 2.8.2 In-Reply-To: <20160503000508.556845508@linuxfoundation.org> References: <20160503000508.556845508@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thierry Reding commit 70a7fb80e85ae7f78f8e90cec3fbd862ea6a4d4b upstream. Commit fa731ac7ea04 ("regulator: core: avoid unused variable warning") introduced a subtle change in how supplies are locked. Where previously code was always locking the regulator of the current iteration, the new implementation only locks the regulator if it has a supply. For any given power tree that means that the root will never get locked. On the other hand the regulator_unlock_supply() will still release all the locks, which in turn causes the lock debugging code to warn about a mutex being unlocked which wasn't locked. Cc: Mark Brown Cc: Arnd Bergmann Fixes: fa731ac7ea04 ("regulator: core: avoid unused variable warning") Signed-off-by: Thierry Reding Signed-off-by: Mark Brown Cc: Guenter Roeck Signed-off-by: Greg Kroah-Hartman --- drivers/regulator/core.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -132,6 +132,14 @@ static bool have_full_constraints(void) return has_full_constraints || of_have_populated_dt(); } +static inline struct regulator_dev *rdev_get_supply(struct regulator_dev *rdev) +{ + if (rdev && rdev->supply) + return rdev->supply->rdev; + + return NULL; +} + /** * regulator_lock_supply - lock a regulator and its supplies * @rdev: regulator source @@ -140,8 +148,7 @@ static void regulator_lock_supply(struct { int i; - mutex_lock(&rdev->mutex); - for (i = 1; rdev; rdev = rdev->supply->rdev, i++) + for (i = 0; rdev; rdev = rdev_get_supply(rdev), i++) mutex_lock_nested(&rdev->mutex, i); }