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 220E1370AC2 for ; Fri, 4 Sep 2026 04:38:31 +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=1788496713; cv=none; b=Z4MSJB/qRcsC2leMU0UECI2xSlkxj38Mf3XRWnSuzGMQrYPhE3yw+MvTK5BYXaHK8VIRtAkacbi56lroB+vkcWO2DzBEAUSIJgTpIJKegHzJ7fyIzUJAPo4aCAVNUplgFPXN+UiNk/qd8OFTjROGoxlpGBZwMS5db/q0OAfORnw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788496713; c=relaxed/simple; bh=zg7FIUcrqBupIA1cQWjHqHVXocJW1d+MTmUKYvt7h/k=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=Oyk6CeVThsBuYUO3PDQsupoHgZ/rDq8U7ALRY33IrE/qGaKFkjzo33GSI86iK+xf4Gz7w6ekLx4NLJrQACyXb1AKDu5H28v86PT7Z8jfBcv3wI6RhEoMHtr1eqCeZtR47z+Ecg+CUIBnLzHzmN6NbpfN0f0iv1Yx+Tpvgv0hpc0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xCOKnNde; 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="xCOKnNde" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F3E01F00A3D; Fri, 4 Sep 2026 04:38:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788496711; bh=ysIxFugsqljee6mA7GABnKBAx4Iu8j6qeMmqf0jW+bw=; h=Subject:To:Cc:From:Date; b=xCOKnNdeD7wX3edwkwAzF4fRMma3M/S5psf1faNzQ7Ka5mr+nG0F/O14OzX0oLzuC Ry3RfpQPSpRVdhSIMQIdC+cXdM97HaM4TSuNKtsp4dYQO01gAA1AvaEmuc8Kf7QgCT GuiDYdb/u5sdj9nDSrvJzEMeGw7TaLHLpkuFhIJQ= Subject: FAILED: patch "[PATCH] wifi: rtl8xxxu: fix use-after-free from rx_urb_wq on stop" failed to apply to 6.1-stable tree To: fanwu01@zju.edu.cn,pkshih@realtek.com Cc: From: Date: Fri, 04 Sep 2026 06:38:18 +0200 Message-ID: <2026090418-judgingly-easiest-25f4@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 6c080026ecc17eecb103f8927c64ea73a74bb818 # git commit -s git send-email --to '' --in-reply-to '2026090418-judgingly-easiest-25f4@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 6c080026ecc17eecb103f8927c64ea73a74bb818 Mon Sep 17 00:00:00 2001 From: Fan Wu Date: Tue, 30 Jun 2026 03:31:17 +0000 Subject: [PATCH] wifi: rtl8xxxu: fix use-after-free from rx_urb_wq on stop rtl8xxxu arms rx_urb_wq from the RX completion path: rtl8xxxu_rx_complete() hands the URB to rtl8xxxu_queue_rx_urb(), which queues it on rx_urb_pending_list and, once the list grows past RTL8XXXU_RX_URB_PENDING_WATER, schedules rx_urb_wq. The worker rtl8xxxu_rx_urb_work() drains rx_urb_pending_list, recovers priv through container_of, and resubmits each URB through rtl8xxxu_submit_rx_urb(), which anchors it on rx_anchor and dereferences priv->udev. rtl8xxxu_stop() cancels the sibling work items (c2hcmd_work, ra_watchdog, update_beacon_work) but never cancels rx_urb_wq, so a worker armed during the last burst of RX traffic can run rtl8xxxu_rx_urb_work() after rtl8xxxu_disconnect() has called ieee80211_free_hw(), which frees priv, producing a use-after-free. The window opens under active RX traffic (pending count above the watermark) followed by a disconnect. There are two teardown races to close: * rtl8xxxu_queue_rx_urb() decided whether to enqueue under rx_urb_lock but called schedule_work() after dropping the lock. A completion that observed shutdown == false and released the lock could then call schedule_work() after rtl8xxxu_stop() had set shutdown and cancel_work_sync() had already returned, arming the worker to run after the teardown. Move schedule_work() under the same !shutdown branch so the arming decision is atomic with the shutdown check. * rtl8xxxu_rx_urb_work() anchors every URB it drained back onto rx_anchor through rtl8xxxu_submit_rx_urb(). A worker still running when usb_kill_anchored_urbs(&priv->rx_anchor) returned would submit a URB that escaped the kill. In rtl8xxxu_stop(), call cancel_work_sync(&priv->rx_urb_wq) before the kill so the worker is drained first. After priv->shutdown is set under rx_urb_lock, completions can no longer queue rx_urb_wq. cancel_work_sync() then drains the last queued or running worker, and the following usb_kill_anchored_urbs() kills the URBs it may have submitted. rtl8xxxu_disconnect() is covered because ieee80211_unregister_hw() guarantees .stop() runs for a live interface before ieee80211_free_hw() frees priv. The probe error path needs no cancel: rx_urb_wq is INIT_WORK()'d there but cannot have been scheduled, since no URB is submitted before ieee80211_register_hw() succeeds. This bug was found by static analysis. Fixes: 26f1fad29ad9 ("New driver: rtl8xxxu (mac80211)") Cc: stable@vger.kernel.org Signed-off-by: Fan Wu Signed-off-by: Ping-Ke Shih Link: https://patch.msgid.link/20260630033117.3377-1-fanwu01@zju.edu.cn diff --git a/drivers/net/wireless/realtek/rtl8xxxu/core.c b/drivers/net/wireless/realtek/rtl8xxxu/core.c index 4e8a4769603c..bddbd0990de7 100644 --- a/drivers/net/wireless/realtek/rtl8xxxu/core.c +++ b/drivers/net/wireless/realtek/rtl8xxxu/core.c @@ -5837,14 +5837,19 @@ static void rtl8xxxu_queue_rx_urb(struct rtl8xxxu_priv *priv, { struct sk_buff *skb; unsigned long flags; - int pending = 0; spin_lock_irqsave(&priv->rx_urb_lock, flags); if (!priv->shutdown) { list_add_tail(&rx_urb->list, &priv->rx_urb_pending_list); priv->rx_urb_pending_count++; - pending = priv->rx_urb_pending_count; + /* + * Arm the worker under rx_urb_lock so this is atomic with the + * shutdown check: moving it out of the lock would let a + * completion arm the work after rtl8xxxu_stop() canceled it. + */ + if (priv->rx_urb_pending_count > RTL8XXXU_RX_URB_PENDING_WATER) + schedule_work(&priv->rx_urb_wq); } else { skb = (struct sk_buff *)rx_urb->urb.context; dev_kfree_skb_irq(skb); @@ -5852,9 +5857,6 @@ static void rtl8xxxu_queue_rx_urb(struct rtl8xxxu_priv *priv, } spin_unlock_irqrestore(&priv->rx_urb_lock, flags); - - if (pending > RTL8XXXU_RX_URB_PENDING_WATER) - schedule_work(&priv->rx_urb_wq); } static void rtl8xxxu_rx_urb_work(struct work_struct *work) @@ -7506,6 +7508,13 @@ static void rtl8xxxu_stop(struct ieee80211_hw *hw, bool suspend) priv->shutdown = true; spin_unlock_irqrestore(&priv->rx_urb_lock, flags); + /* + * Cancel before killing rx_anchor: the worker re-anchors every URB + * it drained via rtl8xxxu_submit_rx_urb(), so a worker still running + * after the kill could submit a URB that escapes it. + */ + cancel_work_sync(&priv->rx_urb_wq); + usb_kill_anchored_urbs(&priv->rx_anchor); usb_kill_anchored_urbs(&priv->tx_anchor); if (priv->usb_interrupts)