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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 444DCC2BB55 for ; Thu, 16 Apr 2020 13:46:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EEE321744 for ; Thu, 16 Apr 2020 13:46:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587044764; bh=YDlUlH9cxoPoePJ/BVt1VLVyGDJmuuZt3f/vtA5eHsQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ejXac+QDtU88oZc7x03BIDbxEovNp036QLZPHDH8UQxbvyL6FmdC4vH0rarrD+YAa NKib9GVv5H3UnSZFONrMesEiGyzCwFAG5Sq4AYINnWgXFzjh11n8umyeUkr/9EBDbv 7PL8xVmie3pkh4WM/4JzIg3bhVo5PCCidAs/9zD0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2898553AbgDPNqB (ORCPT ); Thu, 16 Apr 2020 09:46:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:46416 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2896991AbgDPNet (ORCPT ); Thu, 16 Apr 2020 09:34:49 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5A114208E4; Thu, 16 Apr 2020 13:34:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587044086; bh=YDlUlH9cxoPoePJ/BVt1VLVyGDJmuuZt3f/vtA5eHsQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=s3TW3EGxFY05S9GJNNi8r62/16dHMqtu1Sm7asQUsjUJxuIJP5JMoDUHFdoE7Svto 6GWEHykPB5dJQ88uQHDeCdXDVvTLA00e0SRwDbPYMtsnXwKOr37NjiOGCPRZR1Gl1X v102phOo+qrs/U73fKQZT7YqZncURW/d3Q9WtjOs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Liguang Zhang , James Morse , Catalin Marinas , Sasha Levin Subject: [PATCH 5.5 034/257] firmware: arm_sdei: fix double-lock on hibernate with shared events Date: Thu, 16 Apr 2020 15:21:25 +0200 Message-Id: <20200416131330.227891067@linuxfoundation.org> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20200416131325.891903893@linuxfoundation.org> References: <20200416131325.891903893@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: James Morse [ Upstream commit 6ded0b61cf638bf9f8efe60ab8ba23db60ea9763 ] SDEI has private events that must be registered on each CPU. When CPUs come and go they must re-register and re-enable their private events. Each event has flags to indicate whether this should happen to protect against an event being registered on a CPU coming online, while all the others are unregistering the event. These flags are protected by the sdei_list_lock spinlock, because the cpuhp callbacks can't take the mutex. Hibernate needs to unregister all events, but keep the in-memory re-register and re-enable as they are. sdei_unregister_shared() takes the spinlock to walk the list, then calls _sdei_event_unregister() on each shared event. _sdei_event_unregister() tries to take the same spinlock to update re-register and re-enable. This doesn't go so well. Push the re-register and re-enable updates out to their callers. sdei_unregister_shared() doesn't want these values updated, so doesn't need to do anything. This also fixes shared events getting lost over hibernate as this path made them look unregistered. Fixes: da351827240e ("firmware: arm_sdei: Add support for CPU and system power states") Reported-by: Liguang Zhang Signed-off-by: James Morse Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin --- drivers/firmware/arm_sdei.c | 32 +++++++++++++++----------------- 1 file changed, 15 insertions(+), 17 deletions(-) diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c index a479023fa036e..77eaa9a2fd156 100644 --- a/drivers/firmware/arm_sdei.c +++ b/drivers/firmware/arm_sdei.c @@ -491,11 +491,6 @@ static int _sdei_event_unregister(struct sdei_event *event) { lockdep_assert_held(&sdei_events_lock); - spin_lock(&sdei_list_lock); - event->reregister = false; - event->reenable = false; - spin_unlock(&sdei_list_lock); - if (event->type == SDEI_EVENT_TYPE_SHARED) return sdei_api_event_unregister(event->event_num); @@ -518,6 +513,11 @@ int sdei_event_unregister(u32 event_num) break; } + spin_lock(&sdei_list_lock); + event->reregister = false; + event->reenable = false; + spin_unlock(&sdei_list_lock); + err = _sdei_event_unregister(event); if (err) break; @@ -585,26 +585,15 @@ static int _sdei_event_register(struct sdei_event *event) lockdep_assert_held(&sdei_events_lock); - spin_lock(&sdei_list_lock); - event->reregister = true; - spin_unlock(&sdei_list_lock); - if (event->type == SDEI_EVENT_TYPE_SHARED) return sdei_api_event_register(event->event_num, sdei_entry_point, event->registered, SDEI_EVENT_REGISTER_RM_ANY, 0); - err = sdei_do_cross_call(_local_event_register, event); - if (err) { - spin_lock(&sdei_list_lock); - event->reregister = false; - event->reenable = false; - spin_unlock(&sdei_list_lock); - + if (err) sdei_do_cross_call(_local_event_unregister, event); - } return err; } @@ -632,8 +621,17 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg) break; } + spin_lock(&sdei_list_lock); + event->reregister = true; + spin_unlock(&sdei_list_lock); + err = _sdei_event_register(event); if (err) { + spin_lock(&sdei_list_lock); + event->reregister = false; + event->reenable = false; + spin_unlock(&sdei_list_lock); + sdei_event_destroy(event); pr_warn("Failed to register event %u: %d\n", event_num, err); -- 2.20.1