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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 AB654C43463 for ; Fri, 18 Sep 2020 03:06:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F6DF23119 for ; Fri, 18 Sep 2020 03:06:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600398390; bh=1421uzvkwaBdxLSU4zsKRga+Ar+Yd6i16Q6f6C1NZE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=re7jYty+ge/hswBzahBKNFlFzR4gY+nRbTFC718icjBT3c3HYzqZLlS1scuvf6BSG CQQJf03aWdkd2TwB5z6ZDxtLAdGAazmIAfHYcY/tdXbqpGyndfXxSfxM1smLcgKdaZ 0aeSF9ezpQqR9J3fk7lxeHoCabjfB06CzAP/42mU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727489AbgIRDGH (ORCPT ); Thu, 17 Sep 2020 23:06:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:51218 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727245AbgIRCEJ (ORCPT ); Thu, 17 Sep 2020 22:04:09 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A2006235F8; Fri, 18 Sep 2020 02:04:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600394649; bh=1421uzvkwaBdxLSU4zsKRga+Ar+Yd6i16Q6f6C1NZE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l4I4PRBIaFCTudYenmXvP4cQ+aCmE0UBzq590Qtfy7Jmfm3Vii9wblfmG/F8t/bEX GASuOrbAiXuQWOey7BG+aB0JPrlYGa45Gfx/heyc/kf1wu7BNYijObjpdm76T0b8Kc dEUoB+5mhyQhiiG8Rl+EkaPC2ZKj21dnPTv2rL5k= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: James Morse , Catalin Marinas , Sasha Levin Subject: [PATCH AUTOSEL 5.4 146/330] firmware: arm_sdei: Use cpus_read_lock() to avoid races with cpuhp Date: Thu, 17 Sep 2020 21:58:06 -0400 Message-Id: <20200918020110.2063155-146-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918020110.2063155-1-sashal@kernel.org> References: <20200918020110.2063155-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@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