From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) (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 B5AE13CB8E9 for ; Wed, 19 Aug 2026 08:06:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=60.244.123.138 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787126805; cv=none; b=HDWpmSKiaYXLIbChKlRlX9k0UDfr/Y0NCZ7nqQz9/GCC93a2mxyeUeVbF6EtnDKVS5a+9uHKJzg7kPlCv0GsIZ0RbVK4DTwsjqU45hinNTy9THynlYlLwHKQtL8rp36dTEvEiMMNc/P0Qk9FvLzpLqatOQ7fBKtsbvnmkju90zI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787126805; c=relaxed/simple; bh=eoXaDRe6mDv/U6CI2Py2v0epG/drLl03/Ipm0jnRZk0=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=cn+svqknp9FqxwdqEsK1MqBp3BgebI9WM0jt7Rz63+hLPpSudXauvgGbpwgjzLXS91VUsuL+04iDE0GN+8T9PqovukJjjX+Fa5m8Tn3pEtm1bU07gqYxtOmJs76AGlvwMGyUzu6dXmE33yoqzsCCxFQqDRrWb9ZAhnRX1sKduqk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mediatek.com; spf=pass smtp.mailfrom=mediatek.com; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b=m48oqPCz; arc=none smtp.client-ip=60.244.123.138 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mediatek.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mediatek.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b="m48oqPCz" X-UUID: e36ea69c9ba411f1b1788b6acf885367-20260819 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:CC:To:From; bh=XX78+L5F/1RXl2iNxigSzWE8NOyLgddkL6ovb0LMu8s=; b=m48oqPCzAdb3nTsT0nQtm2Vi5JlJN8rACDpaIVHhppWbnsmqCePD8ml/QLNQYxQiG7k1EAIjDvsItY+k8wKP5MQWDeRikUMUH+yDeLNpU7LAsnGLXwXykfzjPGox1QceLHN2zb9K84pBU1n3Een5DK/Aw+S23UgV2p4k8sMCfU0=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.19,REQID:8c24fa35-bf89-4ce2-aec9-21b4fb60f00c,IP:0,U RL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION: release,TS:0 X-CID-META: VersionHash:7db8b62,CLOUDID:b5282ffe-f4cb-4ad2-b022-e3ac6648bf25,B ulkID:nil,BulkQuantity:0,SF:81|82|102|836|865|888|898,TC:-5,Content:0|15|5 0|99,EDM:-3,IP:nil,URL:0,File:130,RT:0,Bulk:nil,QS:nil,BEC:-1,COL:0,OSI:0, OSA:0,AV:0,LES:1,SPR:NO,DKR:0,DKP:0,BRR:0,BRE:0,ARC:0 X-CID-BVR: 2,SSN|SDN X-CID-BAS: 2,SSN|SDN,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: e36ea69c9ba411f1b1788b6acf885367-20260819 Received: from mtkmbs11n2.mediatek.inc [(172.21.101.187)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 885025233; Wed, 19 Aug 2026 16:06:31 +0800 Received: from mtkmbs13n2.mediatek.inc (172.21.101.108) by MTKMBS09N2.mediatek.inc (172.21.101.94) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.29; Wed, 19 Aug 2026 16:06:30 +0800 Received: from mtksitap99.mediatek.inc (10.233.130.16) by mtkmbs13n2.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.2562.29 via Frontend Transport; Wed, 19 Aug 2026 16:06:30 +0800 From: Eason Lai To: Eason Lai CC: , Devin Wittmayer Subject: [PATCH v3 2/2] wifi: mt76: fix memory leak in USB TX path Date: Wed, 19 Aug 2026 16:06:28 +0800 Message-ID: <20260819080628.1056925-3-eason.lai@mediatek.com> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20260819080628.1056925-1-eason.lai@mediatek.com> References: <20260819080628.1056925-1-eason.lai@mediatek.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain When errors occur in mt76u_tx_queue_skb(), the skb is not properly freed, leading to memory leaks. This happens when: - The queue is full - tx_prepare_skb() drops zero-length frames (such as WMM NULL frames) to prevent hardware TX hangs - Buffer setup fails Fix by properly releasing the skb with ieee80211_tx_status_ext() when the queue is full or tx_prepare_skb() fails, and using mt76_tx_complete_skb() when mt76u_tx_setup_buffers() fails (since tx_prepare_skb() has already succeeded and may have allocated resources that need cleanup) Fixes: b40b15e1521f ("mt76: add usb support to mt76 layer") Cc: stable@vger.kernel.org Tested-by: Devin Wittmayer Signed-off-by: Eason Lai --- v2: - add error handling for queue full and tx_prepare_skb() - correct error handling for mt76u_tx_setup_buffers() v3: add Tested-by: Devin Wittmayer and cc stable --- drivers/net/wireless/mediatek/mt76/usb.c | 31 ++++++++++++++++++++---- 1 file changed, 26 insertions(+), 5 deletions(-) diff --git a/drivers/net/wireless/mediatek/mt76/usb.c b/drivers/net/wireless/mediatek/mt76/usb.c index a9af3aa6b80a..dfc12f6944a7 100644 --- a/drivers/net/wireless/mediatek/mt76/usb.c +++ b/drivers/net/wireless/mediatek/mt76/usb.c @@ -893,6 +893,9 @@ mt76u_tx_queue_skb(struct mt76_phy *phy, struct mt76_queue *q, enum mt76_txq_id qid, struct sk_buff *skb, struct mt76_wcid *wcid, struct ieee80211_sta *sta) { + struct ieee80211_tx_status status = { + .sta = sta, + }; struct mt76_tx_info tx_info = { .skb = skb, }; @@ -900,17 +903,27 @@ mt76u_tx_queue_skb(struct mt76_phy *phy, struct mt76_queue *q, u16 idx = q->head; int err; - if (q->queued == q->ndesc) - return -ENOSPC; + if (q->queued == q->ndesc) { + err = -ENOSPC; + goto err_free_skb; + } skb->prev = skb->next = NULL; err = dev->drv->tx_prepare_skb(dev, NULL, qid, wcid, sta, &tx_info); if (err < 0) - return err; + goto err_free_skb; err = mt76u_tx_setup_buffers(dev, tx_info.skb, q->entry[idx].urb); - if (err < 0) - return err; + if (err < 0) { + /* + * mt76_tx_status_skb_get() walks the idr and dereferences + * a freed skb. This SKB is not counted in non-AQL counter + * due to error return, so using 0xffff as wcid to keep + * balanced. + */ + mt76_tx_complete_skb(dev, 0xffff, tx_info.skb); + goto err_ret; + } mt76u_fill_bulk_urb(dev, USB_DIR_OUT, q->ep, q->entry[idx].urb, mt76u_complete_tx, &q->entry[idx]); @@ -921,6 +934,14 @@ mt76u_tx_queue_skb(struct mt76_phy *phy, struct mt76_queue *q, q->queued++; return idx; + +err_free_skb: + status.skb = tx_info.skb; + spin_lock_bh(&dev->rx_lock); + ieee80211_tx_status_ext(dev->hw, &status); + spin_unlock_bh(&dev->rx_lock); +err_ret: + return err; } static void mt76u_tx_kick(struct mt76_dev *dev, struct mt76_queue *q) -- 2.45.2