From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752193AbcF3MtV (ORCPT ); Thu, 30 Jun 2016 08:49:21 -0400 Received: from mga09.intel.com ([134.134.136.24]:2350 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751945AbcF3MtS (ORCPT ); Thu, 30 Jun 2016 08:49:18 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,552,1459839600"; d="scan'208";a="131224668" From: Alexander Shishkin To: Greg KH Cc: laurent.fert@intel.com, yann.fouassier@intel.com, linux-kernel@vger.kernel.org, Alexander Shishkin Subject: [QUEUED fixes v20160630 1/2] intel_th: Fix a deadlock in modprobing Date: Thu, 30 Jun 2016 15:46:01 +0300 Message-Id: <1467290762-15406-2-git-send-email-alexander.shishkin@linux.intel.com> X-Mailer: git-send-email 2.8.0.rc3 In-Reply-To: <1467290762-15406-1-git-send-email-alexander.shishkin@linux.intel.com> References: <1467290762-15406-1-git-send-email-alexander.shishkin@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Driver initialization tries to request a hub (GTH) driver module from its probe callback, resulting in a deadlock. This patch solves the problem by adding a deferred work for requesting the hub module. Signed-off-by: Alexander Shishkin --- drivers/hwtracing/intel_th/core.c | 35 ++++++++++++++++++++++++++++++++++- drivers/hwtracing/intel_th/intel_th.h | 3 +++ 2 files changed, 37 insertions(+), 1 deletion(-) diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c index 1be543e8e4..0b112ae689 100644 --- a/drivers/hwtracing/intel_th/core.c +++ b/drivers/hwtracing/intel_th/core.c @@ -465,6 +465,38 @@ static struct intel_th_subdevice { }, }; +#ifdef CONFIG_MODULES +static void __intel_th_request_hub_module(struct work_struct *work) +{ + struct intel_th *th = container_of(work, struct intel_th, + request_module_work); + + request_module("intel_th_%s", th->hub->name); +} + +static int intel_th_request_hub_module(struct intel_th *th) +{ + INIT_WORK(&th->request_module_work, __intel_th_request_hub_module); + schedule_work(&th->request_module_work); + + return 0; +} + +static void intel_th_request_hub_module_flush(struct intel_th *th) +{ + flush_work(&th->request_module_work); +} +#else +static inline int intel_th_request_hub_module(struct intel_th *th) +{ + return -EINVAL; +} + +static inline void intel_th_request_hub_module_flush(struct intel_th *th) +{ +} +#endif /* CONFIG_MODULES */ + static int intel_th_populate(struct intel_th *th, struct resource *devres, unsigned int ndevres, int irq) { @@ -535,7 +567,7 @@ static int intel_th_populate(struct intel_th *th, struct resource *devres, /* need switch driver to be loaded to enumerate the rest */ if (subdev->type == INTEL_TH_SWITCH && !req) { th->hub = thdev; - err = request_module("intel_th_%s", subdev->name); + err = intel_th_request_hub_module(th); if (!err) req++; } @@ -652,6 +684,7 @@ void intel_th_free(struct intel_th *th) { int i; + intel_th_request_hub_module_flush(th); for (i = 0; i < TH_SUBDEVICE_MAX; i++) if (th->thdev[i] != th->hub) intel_th_device_remove(th->thdev[i]); diff --git a/drivers/hwtracing/intel_th/intel_th.h b/drivers/hwtracing/intel_th/intel_th.h index 0df22e3067..0482848260 100644 --- a/drivers/hwtracing/intel_th/intel_th.h +++ b/drivers/hwtracing/intel_th/intel_th.h @@ -205,6 +205,9 @@ struct intel_th { int id; int major; +#ifdef CONFIG_MODULES + struct work_struct request_module_work; +#endif /* CONFIG_MODULES */ #ifdef CONFIG_INTEL_TH_DEBUG struct dentry *dbg; #endif -- 2.8.1