From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752927AbbA2JAp (ORCPT ); Thu, 29 Jan 2015 04:00:45 -0500 Received: from ip4-83-240-67-251.cust.nbox.cz ([83.240.67.251]:44737 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756097AbbA2JAj (ORCPT ); Thu, 29 Jan 2015 04:00:39 -0500 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jim Lin , Linus Walleij , Jiri Slaby Subject: [PATCH 3.12 141/176] pinctrl: Fix two deadlocks Date: Wed, 28 Jan 2015 15:29:31 +0100 Message-Id: X-Mailer: git-send-email 2.2.2 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jim Lin 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit db93facfb0ef542aa5d8079e47580b3e669a4d82 upstream. This patch is to fix two deadlock cases. Deadlock 1: CPU #1 pinctrl_register-> pinctrl_get -> create_pinctrl (Holding lock pinctrl_maps_mutex) -> get_pinctrl_dev_from_devname (Trying to acquire lock pinctrldev_list_mutex) CPU #0 pinctrl_unregister (Holding lock pinctrldev_list_mutex) -> pinctrl_put ->> pinctrl_free -> pinctrl_dt_free_maps -> pinctrl_unregister_map (Trying to acquire lock pinctrl_maps_mutex) Simply to say CPU#1 is holding lock A and trying to acquire lock B, CPU#0 is holding lock B and trying to acquire lock A. Deadlock 2: CPU #3 pinctrl_register-> pinctrl_get -> create_pinctrl (Holding lock pinctrl_maps_mutex) -> get_pinctrl_dev_from_devname (Trying to acquire lock pinctrldev_list_mutex) CPU #2 pinctrl_unregister (Holding lock pctldev->mutex) -> pinctrl_put ->> pinctrl_free -> pinctrl_dt_free_maps -> pinctrl_unregister_map (Trying to acquire lock pinctrl_maps_mutex) CPU #0 tegra_gpio_request (Holding lock pinctrldev_list_mutex) -> pinctrl_get_device_gpio_range (Trying to acquire lock pctldev->mutex) Simply to say CPU#3 is holding lock A and trying to acquire lock D, CPU#2 is holding lock B and trying to acquire lock A, CPU#0 is holding lock D and trying to acquire lock B. Signed-off-by: Jim Lin Signed-off-by: Linus Walleij Signed-off-by: Jiri Slaby --- drivers/pinctrl/core.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c index a1ffae4c3770..260a2551d612 100644 --- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -1796,14 +1796,15 @@ void pinctrl_unregister(struct pinctrl_dev *pctldev) if (pctldev == NULL) return; - mutex_lock(&pinctrldev_list_mutex); mutex_lock(&pctldev->mutex); - pinctrl_remove_device_debugfs(pctldev); + mutex_unlock(&pctldev->mutex); if (!IS_ERR(pctldev->p)) pinctrl_put(pctldev->p); + mutex_lock(&pinctrldev_list_mutex); + mutex_lock(&pctldev->mutex); /* TODO: check that no pinmuxes are still active? */ list_del(&pctldev->node); /* Destroy descriptor tree */ -- 2.2.2