From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754242AbbK0Nro (ORCPT ); Fri, 27 Nov 2015 08:47:44 -0500 Received: from mout.kundenserver.de ([212.227.126.130]:60140 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753314AbbK0Nrk (ORCPT ); Fri, 27 Nov 2015 08:47:40 -0500 From: Arnd Bergmann To: Mark Brown Cc: Peter Zijlstra , Sascha Hauer , "linux-kernel@vger.kernel.org" , Liam Girdwood , Geert Uytterhoeven , Ingo Molnar , "linux-arm-kernel@lists.infradead.org" Subject: [PATCH, RESEND] regulator: core: fix regulator_lock_supply regression Date: Fri, 27 Nov 2015 14:46:41 +0100 Message-ID: <3504080.aWaTxHbgxH@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:DHx0EA1KdqmuTr8Kp95WL+v9zYwVsn27AnZt7hzD2EpFBTJrdsG IU/KmtcU1EbXCUxSiqoEm9hFR7fEcJq//MSMc337zqNCqajf3GADlEMXRqP4W1wkryKa+YT cfFrm36dW0KyETa6VjmCtGHyYEbf2n2e6UhcHs1a1RgxAjKKtIL0e4SbQnRf0ljywVORNEq /6jhTq5Mvjo51EQEXFmSQ== X-UI-Out-Filterresults: notjunk:1;V01:K0:nEH3w5HV9BA=:iI8P4VCwTG52E/rVQLETu7 8ModolHc8QiAb3dD5h/hA/0pwxyDyEHPRqT3QHjlUQowOxtQrNved3Hp4j9s68ssHRyLT1HMx 3S1sC6LxX7VrRxsNPDy+WdhRf7IYsmt1r+snP6/zUVF8VngmyVKlXOESd8jb0reFczoqfRFHl OOwc3ig+MvNvAAMfHW5YPwn+4TYvtHBb0WV6/ST/2Az97pNtdAfu0rduaL0VCmzes0bS0GWqs 5e8TX/kbPvtP3ejrXREOOTyfgQnA6Rduq8M8/mLWoMdRoMvMU+nNAOtnrLw2yU8M8ecY/EHRy 5gM0/2PpxLMuDCrs51NwMEhF90cSuxe6tM1SGb4vCwA9sC9XeM1OvIpz0LGxusqDwSQtHhFuC S6+RExUwaRcOd/TL5G71CkP698VeCh9ScVvBH5Sxohs0AT/u+vhJ36FxSzmmlRdA+gkAVXx9e x4YtaQZjdv3I5g3cMIY0qBwZhha0YqDEeAkjwZ8i67WUVvY4ZMmkLkqjrKdWpybJCIHLvCvkt QE7H9+Y2fT92DraLT59Y5Oi/3vRmvl5zc/AWIvRjRT3gjzsKNXYaEnYCg9RsTDat1Yqe6J2/o YD0KkN+oEZ0VfQhwr+5CCHpvRoOQHAJNn+gu3FOZne7p3sEH9eVKA5ySo4MkHOCnSRQqlJij4 9zbJ7FjYWk6sPo8nAZLuFEHIvJkzUZCenk2t5NsC2Oh6BDFMaufWb6GfOE9FcvPgz96GiQtI8 zG+9UjoVEM3lyE2n Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As noticed by Geert Uytterhoeven, my patch to avoid a harmless build warning in regulator_lock_supply() was total crap and introduced a real bug: > [ BUG: bad unlock balance detected! ] > kworker/u4:0/6 is trying to release lock (&rdev->mutex) at: > [] regulator_set_voltage+0x38/0x50 we still lock the regulator supplies, but not the actual regulators, so we are missing a lock, and the unlock is unbalanced. This rectifies it by first locking the regulator device itself before using the same loop as before to lock its supplies. Reported-by: Geert Uytterhoeven Signed-off-by: Arnd Bergmann Fixes: 716fec9d1965 ("[SUBMITTED] regulator: core: avoid unused variable warning") --- rebased on top of regulators.git #for-next diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index c9bdca5f3b9b..89e4dcb84758 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -140,7 +140,8 @@ static void regulator_lock_supply(struct regulator_dev *rdev) { int i; - for (i = 0; rdev->supply; rdev = rdev->supply->rdev, i++) + mutex_lock(&rdev->mutex); + for (i = 1; rdev->supply; rdev = rdev->supply->rdev, i++) mutex_lock_nested(&rdev->mutex, i); }