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=-18.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 805B5C48BCD for ; Tue, 8 Jun 2021 19:11:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DFD861263 for ; Tue, 8 Jun 2021 19:11:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235986AbhFHTNt (ORCPT ); Tue, 8 Jun 2021 15:13:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:39404 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235918AbhFHTDH (ORCPT ); Tue, 8 Jun 2021 15:03:07 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9C93F613EF; Tue, 8 Jun 2021 18:45:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623177915; bh=ch1vEVQ71xI48AXdEkUKvg0OTmsLsoATs65g00hhRFU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cQe765u2OtFntR/3jTzr5UyQDEEqGBgdexRzxerOm0tZOBbWhcr0RDK4BenunrWEJ kCJFqnPpfVL9Ze3NXTG8zVyGADEa0kVdZ0x9XHvQ2lwKFZXYsaR2rx5lnvyiuD3HVV z8F0AKR1uie0j3pnREm1Msim/SyLr5vN0drIjus0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lorenzo Bianconi , Felix Fietkau , Sasha Levin Subject: [PATCH 5.12 001/161] mt76: mt7921: add rcu section in mt7921_mcu_tx_rate_report Date: Tue, 8 Jun 2021 20:25:31 +0200 Message-Id: <20210608175945.526448245@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210608175945.476074951@linuxfoundation.org> References: <20210608175945.476074951@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore 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: Lorenzo Bianconi [ Upstream commit 481fc927c8289919cc0be58666fcd1b7da187a0c ] Introduce rcu section in mt7921_mcu_tx_rate_report before dereferencing wcid pointer otherwise loockdep will report the following issue: [ 115.245740] ============================= [ 115.245754] WARNING: suspicious RCU usage [ 115.245771] 5.10.20 #0 Not tainted [ 115.245784] ----------------------------- [ 115.245816] other info that might help us debug this: [ 115.245830] rcu_scheduler_active = 2, debug_locks = 1 [ 115.245845] 3 locks held by kworker/u4:1/20: [ 115.245858] #0: ffffff80065ab138 ((wq_completion)phy0){+.+.}-{0:0}, at: process_one_work+0x1f8/0x6b8 [ 115.245948] #1: ffffffc01198bdd8 ((work_completion)(&(&dev->mphy.mac_work)->work)){+.+.}-{0:0}, at: process_one_8 [ 115.246027] #2: ffffff8006543ce8 (&dev->mutex#2){+.+.}-{3:3}, at: mt7921_mac_work+0x60/0x2b0 [mt7921e] [ 115.246125] [ 115.246125] stack backtrace: [ 115.246142] CPU: 1 PID: 20 Comm: kworker/u4:1 Not tainted 5.10.20 #0 [ 115.246152] Hardware name: MediaTek MT7622 RFB1 board (DT) [ 115.246168] Workqueue: phy0 mt7921_mac_work [mt7921e] [ 115.246188] Call trace: [ 115.246201] dump_backtrace+0x0/0x1a8 [ 115.246213] show_stack+0x14/0x30 [ 115.246228] dump_stack+0xec/0x134 [ 115.246240] lockdep_rcu_suspicious+0xcc/0xdc [ 115.246255] mt7921_get_wtbl_info+0x2a4/0x310 [mt7921e] [ 115.246269] mt7921_mac_work+0x284/0x2b0 [mt7921e] [ 115.246281] process_one_work+0x2a0/0x6b8 [ 115.246293] worker_thread+0x40/0x440 [ 115.246305] kthread+0x144/0x148 [ 115.246317] ret_from_fork+0x10/0x18 Fixes: 1c099ab44727c ("mt76: mt7921: add MCU support") Signed-off-by: Lorenzo Bianconi Signed-off-by: Felix Fietkau Signed-off-by: Sasha Levin --- drivers/net/wireless/mediatek/mt76/mt7921/mcu.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c index 62afbad77596..9a140e4734b5 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c +++ b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c @@ -404,9 +404,12 @@ mt7921_mcu_tx_rate_report(struct mt7921_dev *dev, struct sk_buff *skb, if (wlan_idx >= MT76_N_WCIDS) return; + + rcu_read_lock(); + wcid = rcu_dereference(dev->mt76.wcid[wlan_idx]); if (!wcid) - return; + goto out; msta = container_of(wcid, struct mt7921_sta, wcid); stats = &msta->stats; @@ -414,6 +417,8 @@ mt7921_mcu_tx_rate_report(struct mt7921_dev *dev, struct sk_buff *skb, /* current rate */ mt7921_mcu_tx_rate_parse(mphy, &peer, &rate, curr); stats->tx_rate = rate; +out: + rcu_read_unlock(); } static void -- 2.30.2