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=-13.5 required=3.0 tests=BAYES_00,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 44F85C4727C for ; Tue, 29 Sep 2020 12:06:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E554A20674 for ; Tue, 29 Sep 2020 12:06:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601381203; bh=1421uzvkwaBdxLSU4zsKRga+Ar+Yd6i16Q6f6C1NZE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=WSZa8BMY0COl+stTMHxjRfBBBqX0lKJ6ooJfKGeE67GbLB3nV7pTyjmGd1CoVNL8a xs9PyBQsBADuxBiHKrnTtLe0xpbLDBUJj8pJcv3iwZZb2YPyeQK2xblDitrhIuXLMR iWnf42529YJONALE407yZ3nZ4Dv2Mr0QJh4a1DiU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731912AbgI2MGl (ORCPT ); Tue, 29 Sep 2020 08:06:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:50310 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730245AbgI2Lhh (ORCPT ); Tue, 29 Sep 2020 07:37:37 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (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 B107623A75; Tue, 29 Sep 2020 11:36:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601379388; bh=1421uzvkwaBdxLSU4zsKRga+Ar+Yd6i16Q6f6C1NZE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=F67zcp2eMOwM3PZ2niGOYbi5itew/7zf9ANhbPV/mwGwFCTWnCviNOLcucC1BOly6 ofN8jT76CJ4IAZ66ZmypJ30pIm1Tu9iemti22VGsIUjMOUtVnLp1aUXpJJaJNqYCg0 kvNIVOIK9/y4wAWg5P4+8T/78brffUiqGYKShVLA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, James Morse , Catalin Marinas , Sasha Levin Subject: [PATCH 5.4 140/388] firmware: arm_sdei: Use cpus_read_lock() to avoid races with cpuhp Date: Tue, 29 Sep 2020 12:57:51 +0200 Message-Id: <20200929110017.253465654@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929110010.467764689@linuxfoundation.org> References: <20200929110010.467764689@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: James Morse [ Upstream commit 54f529a6806c9710947a4f2cdc15d6ea54121ccd ] SDEI has private events that need registering and enabling on each CPU. CPUs can come and go while we are trying to do this. SDEI tries to avoid these problems by setting the reregister flag before the register call, so any CPUs that come online register the event too. Sticking plaster like this doesn't work, as if the register call fails, a CPU that subsequently comes online will register the event before reregister is cleared. Take cpus_read_lock() around the register and enable calls. We don't want surprise CPUs to do the wrong thing if they race with these calls failing. Signed-off-by: James Morse Signed-off-by: Catalin Marinas Signed-off-by: Sasha Levin --- drivers/firmware/arm_sdei.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c index eb2df89d4924f..e497785cd99fe 100644 --- a/drivers/firmware/arm_sdei.c +++ b/drivers/firmware/arm_sdei.c @@ -412,14 +412,19 @@ int sdei_event_enable(u32 event_num) return -ENOENT; } - spin_lock(&sdei_list_lock); - event->reenable = true; - spin_unlock(&sdei_list_lock); + cpus_read_lock(); if (event->type == SDEI_EVENT_TYPE_SHARED) err = sdei_api_event_enable(event->event_num); else err = sdei_do_cross_call(_local_event_enable, event); + + if (!err) { + spin_lock(&sdei_list_lock); + event->reenable = true; + spin_unlock(&sdei_list_lock); + } + cpus_read_unlock(); mutex_unlock(&sdei_events_lock); return err; @@ -621,21 +626,18 @@ 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); - + cpus_read_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); + } else { + spin_lock(&sdei_list_lock); + event->reregister = true; + spin_unlock(&sdei_list_lock); } + cpus_read_unlock(); } while (0); mutex_unlock(&sdei_events_lock); -- 2.25.1