From nobody Fri Sep 25 02:44:22 2026 Received: from cstnet.cn (smtp25.cstnet.cn [159.226.251.25]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 92F054DE713; Thu, 17 Sep 2026 12:21:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.25 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789647681; cv=none; b=QYUAuVHHcRyiB7lDq4ukZD4/hc0xM60HogSE+sbin+bBSMRyepuxcCWdaQcM9vGWUTSFSgpVtvIi+aigMzGrX7CXT3D0WBTpDCbpbe1tsjTerHftA6DrKTddTevZOi0WuIaLwBsmGHuXOmraHXp87vcjBvMGQa6wgeD30l9lJt4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789647681; c=relaxed/simple; bh=EbcdXFHrGSHSe3avH/oWkWcA7aUvQ9U1pf9dYa9aHFQ=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=a71Yu71qCkd8JRaOxHGWJPQsXHc6Ho00RnN6CtaLi4ohfm8MyOQ/UPxNnjTvkdwHt98IgGYMIG0wB3myz9BpAaIMxlwwIOc6exFRAvnO3tXqSfot2cKrEl16Iilc7MhgARAJfCDk7L05McJ5rijA/8C0gd8RbXPaQF/U5LxMfzw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from dfae2b116770.home.arpa (unknown [36.110.52.2]) by APP-05 (Coremail) with SMTP id zQCowAB34jwq26tq1mSACA--.2616S2; Thu, 17 Sep 2026 20:20:58 +0800 (CST) From: Wentao Liang To: angelogioacchino.delregno@collabora.com Cc: kvalo@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-wireless@vger.kernel.org, lorenzo@kernel.org, matthias.bgg@gmail.com, nbd@nbd.name, ryder.lee@mediatek.com, sean.wang@mediatek.com, shayne.chen@mediatek.com, Wentao Liang , stable@vger.kernel.org Subject: [PATCH] wifi: mt76: Fix skb reference leak on USB/SDIO tx_queue_skb error paths Date: Thu, 17 Sep 2026 12:20:58 +0000 Message-Id: <20260917122058.2150817-1-vulab@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: zQCowAB34jwq26tq1mSACA--.2616S2 X-Coremail-Antispam: 1UD129KBjvJXoWxGr1kZFy7XF47uryDZw48Xrb_yoW5Aw1fpF WjgrWYkr18Jr4UG3Z7ua1UX3ZIya1rKFyakryfW34rurWrAr15XFWI9a42vrs3trs5C3W2 qr1ktrsxWrZ2qrDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPqb7Iv0xC_Kw4lb4IE77IF4wAFc2x0x2IEx4CE42xK8VAvwI8I cIk0rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2 AK021l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v2 6F4j6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxV W0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv 7VC0I7IYx2IY67AKxVWUAVWUtwAv7VC2z280aVAFwI0_Gr1j6F4UJwAm72CE4IkC6x0Yz7 v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0E0s8F02x267IIx4CEVc8vx2IErcIFxwAC I402YVCY1x02628vn2kIc2xKxwCY1x0262kKe7AKxVWUtVW8ZwCF04k20xvY0x0EwIxGrw CF04k20xvE74AGY7Cv6cx26r48ZrWUJr1UMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E 5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtV W8ZwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY 1x0267AKxVW8JVWxJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI 0_Gr1j6F4UJwCI42IY6I8E87Iv6xkF7I0E14v26rxl6s0DYxBIdaVFxhVjvjDU0xZFpf9x 07bnXd8UUUUU= X-CM-SenderInfo: pyxotu46lvutnvoduhdfq/1tbiBwgNA2qrrRmKFwABso Content-Type: text/plain; charset="utf-8" The mt76 queue ops take ownership of the skb handed to tx_queue_skb(): the DMA implementation releases it through ieee80211_tx_status_ext() on every error path, but mt76u_tx_queue_skb() and mt76s_tx_queue_skb() just return the error, so the reference is neither queued nor freed. mt76_testmode_tx_pending() relies on that ownership transfer, so it leaks the extra skb reference taken with skb_get() whenever the queue is full or tx_prepare_skb()/mt76u_tx_setup_buffers() fails. Release the skb on the error paths as well. Fixes: b40b15e1521f ("mt76: add usb support to mt76 layer") Fixes: d39b52e31aa6 ("mt76: introduce mt76_sdio module") Cc: stable@vger.kernel.org Signed-off-by: Wentao Liang --- drivers/net/wireless/mediatek/mt76/sdio.c | 13 ++++++++++--- drivers/net/wireless/mediatek/mt76/usb.c | 15 +++++++++++---- 2 files changed, 21 insertions(+), 7 deletions(-) diff --git a/drivers/net/wireless/mediatek/mt76/sdio.c b/drivers/net/wirele= ss/mediatek/mt76/sdio.c index 8bae77c761be..ef82af1f905c 100644 --- a/drivers/net/wireless/mediatek/mt76/sdio.c +++ b/drivers/net/wireless/mediatek/mt76/sdio.c @@ -526,13 +526,15 @@ mt76s_tx_queue_skb(struct mt76_phy *phy, struct mt76_= queue *q, int err, len =3D skb->len; u16 idx =3D q->head; =20 - if (q->queued =3D=3D q->ndesc) - return -ENOSPC; + if (q->queued =3D=3D q->ndesc) { + err =3D -ENOSPC; + goto free_skb; + } =20 skb->prev =3D skb->next =3D NULL; err =3D dev->drv->tx_prepare_skb(dev, NULL, qid, wcid, sta, &tx_info); if (err < 0) - return err; + goto free_skb; =20 q->entry[q->head].skb =3D tx_info.skb; q->entry[q->head].buf_sz =3D len; @@ -544,6 +546,11 @@ mt76s_tx_queue_skb(struct mt76_phy *phy, struct mt76_q= ueue *q, q->queued++; =20 return idx; + +free_skb: + dev_kfree_skb(tx_info.skb); + + return err; } =20 static int diff --git a/drivers/net/wireless/mediatek/mt76/usb.c b/drivers/net/wireles= s/mediatek/mt76/usb.c index 632ae755c7a6..837b0b251b05 100644 --- a/drivers/net/wireless/mediatek/mt76/usb.c +++ b/drivers/net/wireless/mediatek/mt76/usb.c @@ -861,17 +861,19 @@ mt76u_tx_queue_skb(struct mt76_phy *phy, struct mt76_= queue *q, u16 idx =3D q->head; int err; =20 - if (q->queued =3D=3D q->ndesc) - return -ENOSPC; + if (q->queued =3D=3D q->ndesc) { + err =3D -ENOSPC; + goto free_skb; + } =20 skb->prev =3D skb->next =3D NULL; err =3D dev->drv->tx_prepare_skb(dev, NULL, qid, wcid, sta, &tx_info); if (err < 0) - return err; + goto free_skb; =20 err =3D mt76u_tx_setup_buffers(dev, tx_info.skb, q->entry[idx].urb); if (err < 0) - return err; + goto free_skb; =20 mt76u_fill_bulk_urb(dev, USB_DIR_OUT, q->ep, q->entry[idx].urb, mt76u_complete_tx, &q->entry[idx]); @@ -882,6 +884,11 @@ mt76u_tx_queue_skb(struct mt76_phy *phy, struct mt76_q= ueue *q, q->queued++; =20 return idx; + +free_skb: + dev_kfree_skb(tx_info.skb); + + return err; } =20 static void mt76u_tx_kick(struct mt76_dev *dev, struct mt76_queue *q) --=20 2.34.1