From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0A8DC33CAF for ; Thu, 16 Jan 2020 03:29:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF6462084D for ; Thu, 16 Jan 2020 03:29:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729346AbgAPD3E (ORCPT ); Wed, 15 Jan 2020 22:29:04 -0500 Received: from out30-43.freemail.mail.aliyun.com ([115.124.30.43]:53451 "EHLO out30-43.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726587AbgAPD3D (ORCPT ); Wed, 15 Jan 2020 22:29:03 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04452;MF=zhangliguang@linux.alibaba.com;NM=1;PH=DS;RN=3;SR=0;TI=SMTPD_---0TnrNuc._1579145331; Received: from localhost(mailfrom:zhangliguang@linux.alibaba.com fp:SMTPD_---0TnrNuc._1579145331) by smtp.aliyun-inc.com(127.0.0.1); Thu, 16 Jan 2020 11:29:00 +0800 From: luanshi To: james.morse@arm.com Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [V2 1/3] firmware: arm_sdei: fix possible deadlock Date: Thu, 16 Jan 2020 11:28:49 +0800 Message-Id: <1579145331-78633-1-git-send-email-zhangliguang@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We call sdei_reregister_event() with sdei_list_lock held but _sdei_event_register() and sdei_event_destroy() also acquires sdei_list_lock thus creating A-A deadlock. Fixes: da351827240e ("firmware: arm_sdei: Add support for CPU and system power states") Signed-off-by: Liguang Zhang --- drivers/firmware/arm_sdei.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c index a479023..37e9bf0 100644 --- a/drivers/firmware/arm_sdei.c +++ b/drivers/firmware/arm_sdei.c @@ -45,8 +45,11 @@ static asmlinkage void (*sdei_firmware_call)(unsigned long function_id, static unsigned long sdei_entry_point; struct sdei_event { - /* These three are protected by the sdei_list_lock */ + /* protected by the sdei_list_lock */ struct list_head list; + + spinlock_t sdei_event_lock; + /* These two are protected by the sdei_event_lock */ bool reregister; bool reenable; @@ -214,6 +217,7 @@ static struct sdei_event *sdei_event_create(u32 event_num, return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&event->list); + spin_lock_init(&event->sdei_event_lock); event->event_num = event_num; err = sdei_api_event_get_info(event_num, SDEI_EVENT_INFO_EV_PRIORITY, @@ -412,9 +416,9 @@ int sdei_event_enable(u32 event_num) return -ENOENT; } - spin_lock(&sdei_list_lock); + spin_lock(&event->sdei_event_lock); event->reenable = true; - spin_unlock(&sdei_list_lock); + spin_unlock(&event->sdei_event_lock); if (event->type == SDEI_EVENT_TYPE_SHARED) err = sdei_api_event_enable(event->event_num); @@ -491,10 +495,10 @@ static int _sdei_event_unregister(struct sdei_event *event) { lockdep_assert_held(&sdei_events_lock); - spin_lock(&sdei_list_lock); + spin_lock(&event->sdei_event_lock); event->reregister = false; event->reenable = false; - spin_unlock(&sdei_list_lock); + spin_unlock(&event->sdei_event_lock); if (event->type == SDEI_EVENT_TYPE_SHARED) return sdei_api_event_unregister(event->event_num); @@ -585,9 +589,9 @@ static int _sdei_event_register(struct sdei_event *event) lockdep_assert_held(&sdei_events_lock); - spin_lock(&sdei_list_lock); + spin_lock(&event->sdei_event_lock); event->reregister = true; - spin_unlock(&sdei_list_lock); + spin_unlock(&event->sdei_event_lock); if (event->type == SDEI_EVENT_TYPE_SHARED) return sdei_api_event_register(event->event_num, @@ -598,10 +602,10 @@ static int _sdei_event_register(struct sdei_event *event) err = sdei_do_cross_call(_local_event_register, event); if (err) { - spin_lock(&sdei_list_lock); + spin_lock(&event->sdei_event_lock); event->reregister = false; event->reenable = false; - spin_unlock(&sdei_list_lock); + spin_unlock(&event->sdei_event_lock); sdei_do_cross_call(_local_event_unregister, event); } -- 1.8.3.1