Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934457Ab2JXHoO (ORCPT ); Wed, 24 Oct 2012 03:44:14 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:32988 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S934420Ab2JXHoL (ORCPT ); Wed, 24 Oct 2012 03:44:11 -0400 X-IronPort-AV: E=Sophos;i="4.80,639,1344182400"; d="scan'208";a="6058669" Message-ID: <50879BFC.1070202@cn.fujitsu.com> Date: Wed, 24 Oct 2012 15:42:52 +0800 From: Tang Chen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Yasuaki Ishimatsu CC: yinghai@kernel.org, bhelgaas@google.com, lenb@kernel.org, jiang.liu@huawei.com, izumi.taku@jp.fujitsu.com, mihailm@parallels.com, linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] Use kacpi_hotplug_wq to handle container hotplug event. References: <1351058750-4275-1-git-send-email-tangchen@cn.fujitsu.com> <1351058750-4275-2-git-send-email-tangchen@cn.fujitsu.com> <508790AC.5080001@jp.fujitsu.com> In-Reply-To: <508790AC.5080001@jp.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/24 15:43:32, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/24 15:43:35, Serialize complete at 2012/10/24 15:43:35 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-2022-JP Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3599 Lines: 112 Hi Ishimatsu-san: By the way, if you want to reproduce this problem, just modify my patch1 to call __container_notify_cb() directly in container_notify_cb(). And apply my patch2. Then, you add a container, and remove it. The deadlock will be triggered. And this patch is based on Lu Yinghai's tree: git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git for-pci-split-pci-root-hp-2 On 10/24/2012 02:54 PM, Yasuaki Ishimatsu wrote: > Hi Tang, > > 2012/10/24 15:05, Tang Chen wrote: >> As the comments in __acpi_os_execute() said: >> >> We can't run hotplug code in keventd_wq/kacpid_wq/kacpid_notify_wq >> because the hotplug code may call driver .remove() functions, >> which invoke flush_scheduled_work/acpi_os_wait_events_complete >> to flush these workqueues. >> >> we should keep the hotplug code in kacpi_hotplug_wq. >> >> But we have the following call series in kernel now: >> acpi_ev_queue_notify_request() >> |--> acpi_os_execute() >> |--> __acpi_os_execute(type, function, context, 0) >> >> The last parameter 0 makes the container_notify_cb() executed in >> kacpi_notify_wq or kacpid_wq. So, we need to put the real hotplug code >> into kacpi_hotplug_wq. > > I cannot understand the purpose of the patch. > Is the patch a bug fix patch? If yes, what problem happens? > > Thanks, > Yasuaki Ishimatsu > >> >> Signed-off-by: Tang Chen >> --- >> drivers/acpi/container.c | 17 ++++++++++++++++- >> 1 files changed, 16 insertions(+), 1 deletions(-) >> >> diff --git a/drivers/acpi/container.c b/drivers/acpi/container.c >> index 69e2d6b..d300e03 100644 >> --- a/drivers/acpi/container.c >> +++ b/drivers/acpi/container.c >> @@ -35,6 +35,7 @@ >> #include >> #include >> #include >> +#include >> >> #define PREFIX "ACPI: " >> >> @@ -165,14 +166,21 @@ static int container_device_add(struct acpi_device **device, acpi_handle handle) >> return result; >> } >> >> -static void container_notify_cb(acpi_handle handle, u32 type, void *context) >> +static void __container_notify_cb(struct work_struct *work) >> { >> struct acpi_device *device = NULL; >> int result; >> int present; >> acpi_status status; >> + struct acpi_hp_work *hp_work; >> + acpi_handle handle; >> + u32 type; >> u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */ >> >> + hp_work = container_of(work, struct acpi_hp_work, work); >> + handle = hp_work->handle; >> + type = hp_work->type; >> + >> switch (type) { >> case ACPI_NOTIFY_BUS_CHECK: >> /* Fall through */ >> @@ -224,6 +232,13 @@ static void container_notify_cb(acpi_handle handle, u32 type, void *context) >> return; >> } >> >> +static void container_notify_cb(acpi_handle handle, u32 type, >> + void *context) >> +{ >> + alloc_acpi_hp_work(handle, type, context, >> + __container_notify_cb); >> +} >> + >> static acpi_status >> container_walk_namespace_cb(acpi_handle handle, >> u32 lvl, void *context, void **rv) >> > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/