From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756279AbbAHNYr (ORCPT ); Thu, 8 Jan 2015 08:24:47 -0500 Received: from smtp.codeaurora.org ([198.145.11.231]:54639 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754642AbbAHNYq (ORCPT ); Thu, 8 Jan 2015 08:24:46 -0500 From: Ashay Jaiswal To: Liam Girdwood , Mark Brown Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, Anirudh Ghayal , David Collins , Ashay Jaiswal Subject: [PATCH v2] regulator: core: fix race condition in regulator_put() Date: Thu, 8 Jan 2015 18:54:25 +0530 Message-Id: <1420723465-12045-1-git-send-email-ashayj@codeaurora.org> X-Mailer: git-send-email 1.8.2.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The regulator framework maintains a list of consumer regulators for a regulator device and protects it from concurrent access using the regulator device's mutex lock. In the case of regulator_put() the consumer is removed and regulator device's parameters are updated without holding the regulator device's mutex. This would lead to a race condition between the regulator_put() and any function which traverses the consumer list or modifies regulator device's parameters. Fix this race condition by holding the regulator device's mutex in case of regulator_put. Signed-off-by: Ashay Jaiswal --- Changes: V1-->V2: - Updated comment on top of _regulator_put function - Updated lock region drivers/regulator/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index c2554d8..f70a02c 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1488,7 +1488,7 @@ struct regulator *regulator_get_optional(struct device *dev, const char *id) } EXPORT_SYMBOL_GPL(regulator_get_optional); -/* Locks held by regulator_put() */ +/* regulator_list_mutex lock held by regulator_put() */ static void _regulator_put(struct regulator *regulator) { struct regulator_dev *rdev; @@ -1503,12 +1503,14 @@ static void _regulator_put(struct regulator *regulator) /* remove any sysfs entries */ if (regulator->dev) sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name); + mutex_lock(&rdev->mutex); kfree(regulator->supply_name); list_del(®ulator->list); kfree(regulator); rdev->open_count--; rdev->exclusive = 0; + mutex_unlock(&rdev->mutex); module_put(rdev->owner); } -- Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation