From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E3F7942B30E; Thu, 16 Jul 2026 13:50:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784209851; cv=none; b=mTcvHnx73xze2kJy8w8+GKtTRCidJHCBSy9/qtug0ix9u/62MiXl02Jqa8GT0nsFH5fRHCQ9ucDBozUKZ+XncG3kmTxJhTd3EETMFMnnefFKLQrcKu0WBwR3EMvQHFGj+SydCC51P9XCaEEPCcCNyNP9O9F9k0gMybc2VEe6jgk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784209851; c=relaxed/simple; bh=ArQ9rnSUSjcxyZ9hC0q3vbQCYjgtKW6jRL5a9sR+oWU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Hw3NKiIf37fgqLAejgyNDa9iHb9yphwt5AR966uyI/UqSlPiq8xgwaUmDZFjCn4TbYrEbkUrsMUu40ebJDBGV2D8mOGjlHSzoUY64wIA8DDF93iHb5uAtFajNZiK7LtjH0YdXyX8NYcaEAq6Do9qPWK7945ei9dgdEPnD7ioemo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=cHRF9DY7; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="cHRF9DY7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E35751F00A3A; Thu, 16 Jul 2026 13:50:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784209849; bh=sQXyXktmRwdV28xpGceshEF/JNFts0ziqizCyo4+KEI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cHRF9DY7OUMbIUxRihEmpqEfoiWBHuUGaQ43J8L0+mMJWNihEwvSpPVR7ZW74AWrQ QSb2JWtDXAqc9IzHoUr67567XT4qREwC+l4Wxfaxemfv1AOoYwHQgre1xEbDR5dUm9 RRzPAbVGMRqWtWuC+PdaUHv4a7T1abVA1KnwtN0o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Bongani Hlope , Arjan van de Ven , linux-wireless@vger.kernel.org, linux-mediatek@lists.infradead.org, Felix Fietkau , Lorenzo Bianconi , Ryder Lee , Sasha Levin Subject: [PATCH 7.1 341/518] wifi: mt76: mt7921/mt7925: fix NULL dereference in CSA beacon Date: Thu, 16 Jul 2026 15:30:09 +0200 Message-ID: <20260716133055.277340106@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260716133047.772246337@linuxfoundation.org> References: <20260716133047.772246337@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arjan van de Ven [ Upstream commit 351dd7d2c80d23e56dcce6faa4e62bea5b0877c7 ] This patch is based on a BUG as reported by Bongani Hlope at https://lore.kernel.org/all/20260502125824.425d7159@bongani-mini.home.org.za/ When a channel-switch announcement (CSA) beacon is received, cfg80211 queues a wiphy work item that eventually calls mt7921_channel_switch_rx_beacon(). If the station disconnects (or the channel context is otherwise torn down) between the time the work is queued and the time it runs, the driver's dev->new_ctx pointer can already have been cleared to NULL. mt7921_channel_switch_rx_beacon() then dereferences new_ctx unconditionally, triggering a NULL pointer dereference at address 0x0: BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:mt7921_channel_switch_rx_beacon+0x1f/0x100 [mt7921_common] The same missing guard exists in mt7925_channel_switch_rx_beacon(), which shares the same code pattern introduced by the same commit. Add an early-return NULL check for dev->new_ctx in both mt7921_channel_switch_rx_beacon() and mt7925_channel_switch_rx_beacon(). When new_ctx is NULL there is no pending channel switch to process, so returning immediately is the correct and safe action. Fixes: 8aa2f59260eb ("wifi: mt76: mt7921: introduce CSA support") Reported-by: Bongani Hlope Oops-Analysis: http://oops.fenrus.org/reports/lkml/20260502125824.425d7159@bongani-mini.home.org.za/report.html Link: https://lore.kernel.org/all/20260502125824.425d7159@bongani-mini.home.org.za/ Signed-off-by: Arjan van de Ven Cc: linux-wireless@vger.kernel.org Cc: linux-mediatek@lists.infradead.org Cc: Felix Fietkau Cc: Lorenzo Bianconi Cc: Ryder Lee Link: https://patch.msgid.link/20260504145107.1329197-1-arjan@linux.intel.com Signed-off-by: Felix Fietkau Signed-off-by: Sasha Levin --- drivers/net/wireless/mediatek/mt76/mt7921/main.c | 3 +++ drivers/net/wireless/mediatek/mt76/mt7925/main.c | 3 +++ 2 files changed, 6 insertions(+) diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/main.c b/drivers/net/wireless/mediatek/mt76/mt7921/main.c index 3d74fabe74085e..a326f4c95c7c86 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7921/main.c +++ b/drivers/net/wireless/mediatek/mt76/mt7921/main.c @@ -1508,6 +1508,9 @@ static void mt7921_channel_switch_rx_beacon(struct ieee80211_hw *hw, struct mt792x_vif *mvif = (struct mt792x_vif *)vif->drv_priv; u16 beacon_interval = vif->bss_conf.beacon_int; + if (!dev->new_ctx) + return; + if (cfg80211_chandef_identical(&chsw->chandef, &dev->new_ctx->def) && chsw->count) { diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/main.c b/drivers/net/wireless/mediatek/mt76/mt7925/main.c index 79cc30a3b29efc..9dc5ee51eb9f96 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7925/main.c +++ b/drivers/net/wireless/mediatek/mt76/mt7925/main.c @@ -2403,6 +2403,9 @@ static void mt7925_channel_switch_rx_beacon(struct ieee80211_hw *hw, if (ieee80211_vif_is_mld(vif)) return; + if (!dev->new_ctx) + return; + beacon_interval = vif->bss_conf.beacon_int; if (cfg80211_chandef_identical(&chsw->chandef, -- 2.53.0