From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 60D79352936; Fri, 21 Nov 2025 13:37:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763732274; cv=none; b=aF4M0wZV0lCnCJUsBZocp6axLmNIqncxujEl2aEjidX0YZeouxFt/SUlb2JIQ+zkdyLmeUI7EzKGXqIu65gcOMogQgB5v7arqXbgcdqGZoncLCfjKeALDs/lg8rxXtcUPW8I7qo08dAkK6w+yQZUI+J2U1LpjWogdPUZGCAUkZE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763732274; c=relaxed/simple; bh=/RB27YNgfPCoEYTA6/xlV5dPNKpAfB/TBVHUwfFUmjU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Jhb0f4GOsDAZW8hT7fuNTLm1GFZD3F+0lhZFJQNMNIwahF3QWAFMVew74m3GCMuAskCvavrMPI39Cmu8ar8oJt7AwhJRIHcTiOk4or9ppnOrOp+Hv5uq115F25gWqis/bTlF2+Yltwno/Dy8V52gwWdua6AZowtJE0SVnOIoeH0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DO6R61+7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DO6R61+7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB627C4CEF1; Fri, 21 Nov 2025 13:37:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1763732273; bh=/RB27YNgfPCoEYTA6/xlV5dPNKpAfB/TBVHUwfFUmjU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DO6R61+7Kji6Lf4QcRPYRXsGp3qM8xHAv/snrdjDgAJki2EjxSbM0BCPUe0yFp5XY PBDsSnqfs1wgxjvw1prVpaDS5r4nw9Sqy5GgYJos1N7SAYhVX2NOkkWZksqBmmkGTz /qb3lAHeZtsw4ZLRUYjOHS9Irf4bP7MzqZMeezyU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sam Sun , Lizhi Xu , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 030/529] usbnet: Prevents free active kevent Date: Fri, 21 Nov 2025 14:05:29 +0100 Message-ID: <20251121130232.070949014@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20251121130230.985163914@linuxfoundation.org> References: <20251121130230.985163914@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lizhi Xu [ Upstream commit 420c84c330d1688b8c764479e5738bbdbf0a33de ] The root cause of this issue are: 1. When probing the usbnet device, executing usbnet_link_change(dev, 0, 0); put the kevent work in global workqueue. However, the kevent has not yet been scheduled when the usbnet device is unregistered. Therefore, executing free_netdev() results in the "free active object (kevent)" error reported here. 2. Another factor is that when calling usbnet_disconnect()->unregister_netdev(), if the usbnet device is up, ndo_stop() is executed to cancel the kevent. However, because the device is not up, ndo_stop() is not executed. The solution to this problem is to cancel the kevent before executing free_netdev(). Fixes: a69e617e533e ("usbnet: Fix linkwatch use-after-free on disconnect") Reported-by: Sam Sun Closes: https://syzkaller.appspot.com/bug?extid=8bfd7bcc98f7300afb84 Signed-off-by: Lizhi Xu Link: https://patch.msgid.link/20251022024007.1831898-1-lizhi.xu@windriver.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/usb/usbnet.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index fd6b5865ac513..e6a1864f03f94 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -1650,6 +1650,8 @@ void usbnet_disconnect (struct usb_interface *intf) net = dev->net; unregister_netdev (net); + cancel_work_sync(&dev->kevent); + while ((urb = usb_get_from_anchor(&dev->deferred))) { dev_kfree_skb(urb->context); kfree(urb->sg); -- 2.51.0