From patchwork Fri Nov 16 11:12:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Felix Fietkau X-Patchwork-Id: 10685975 X-Patchwork-Delegate: kvalo@adurom.com Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A324D13B5 for ; Fri, 16 Nov 2018 11:12:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 92D032CFC1 for ; Fri, 16 Nov 2018 11:12:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 878D72CFC9; Fri, 16 Nov 2018 11:12:48 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.7 required=2.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 70BA62D03D for ; Fri, 16 Nov 2018 11:12:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389561AbeKPVYa (ORCPT ); Fri, 16 Nov 2018 16:24:30 -0500 Received: from nbd.name ([46.4.11.11]:34388 "EHLO nbd.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727454AbeKPVYa (ORCPT ); Fri, 16 Nov 2018 16:24:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=nbd.name; s=20160729; h=References:In-Reply-To:Message-Id:Date:Subject:To:From:Sender: Reply-To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=mYPvx7azLlciYGjtHNxp8byp4k5zOu3vxA9jtvgzvDE=; b=ThMhyCNVZdP1nvGkA1OuQGmGZr kyrDA94IPEuRYjCgEzO/Jg47FGo6xEgpKC6mrLfVjb6WxMk0nqhgx7Sxomz+LjIQzdYKzhUSO+SqA KdGaXUVykBtTlFTJZHWIgwCcFAmrGc3/FZS5s4eAYRV67d22K4VqcXwHqtHGWhokQgzI=; Received: by maeck.local (Postfix, from userid 501) id 7012F463F114; Fri, 16 Nov 2018 12:12:35 +0100 (CET) From: Felix Fietkau To: linux-wireless@vger.kernel.org Subject: [PATCH v2 3/7] mt76: fix race condition in station removal Date: Fri, 16 Nov 2018 12:12:31 +0100 Message-Id: <20181116111235.86347-3-nbd@nbd.name> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20181116111235.86347-1-nbd@nbd.name> References: <20181116111235.86347-1-nbd@nbd.name> Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP If there are still pending packets in the tx queue when removing a station, it could possibly lead to a call to further attempts to pull packets from the mac80211 tx queue after it has already been removed from the scheduling list. Prevent this from happening by calling synchronize_rcu after deleting the wcid pointer before further cleaning up the tx queues. To be extra careful, ensure that mtxq->list is always initialized properly. Signed-off-by: Felix Fietkau --- v2: keep the call to mt76x02_mac_wcid_setup in place drivers/net/wireless/mediatek/mt76/mt76x02_util.c | 4 +++- drivers/net/wireless/mediatek/mt76/tx.c | 2 +- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/mediatek/mt76/mt76x02_util.c b/drivers/net/wireless/mediatek/mt76/mt76x02_util.c index d2ac1a84668c..1a51193d5d59 100644 --- a/drivers/net/wireless/mediatek/mt76/mt76x02_util.c +++ b/drivers/net/wireless/mediatek/mt76/mt76x02_util.c @@ -216,9 +216,11 @@ int mt76x02_sta_remove(struct ieee80211_hw *hw, struct ieee80211_vif *vif, int idx = msta->wcid.idx; int i; + rcu_assign_pointer(dev->mt76.wcid[idx], NULL); + synchronize_rcu(); + mutex_lock(&dev->mt76.mutex); mt76_tx_status_check(&dev->mt76, &msta->wcid, true); - rcu_assign_pointer(dev->mt76.wcid[idx], NULL); for (i = 0; i < ARRAY_SIZE(sta->txq); i++) mt76_txq_remove(&dev->mt76, sta->txq[i]); mt76x02_mac_wcid_set_drop(dev, idx, true); diff --git a/drivers/net/wireless/mediatek/mt76/tx.c b/drivers/net/wireless/mediatek/mt76/tx.c index e42a24628e4f..f4093dc0e174 100644 --- a/drivers/net/wireless/mediatek/mt76/tx.c +++ b/drivers/net/wireless/mediatek/mt76/tx.c @@ -590,7 +590,7 @@ void mt76_txq_remove(struct mt76_dev *dev, struct ieee80211_txq *txq) spin_lock_bh(&hwq->lock); if (!list_empty(&mtxq->list)) - list_del(&mtxq->list); + list_del_init(&mtxq->list); spin_unlock_bh(&hwq->lock); while ((skb = skb_dequeue(&mtxq->retry_q)) != NULL)