From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F1BDC433EF for ; Mon, 28 Feb 2022 02:05:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232378AbiB1CFw (ORCPT ); Sun, 27 Feb 2022 21:05:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231546AbiB1CFv (ORCPT ); Sun, 27 Feb 2022 21:05:51 -0500 Received: from mail-pj1-x1043.google.com (mail-pj1-x1043.google.com [IPv6:2607:f8b0:4864:20::1043]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BBC6659394; Sun, 27 Feb 2022 18:05:13 -0800 (PST) Received: by mail-pj1-x1043.google.com with SMTP id q8-20020a17090a178800b001bc299b8de1so10012694pja.1; Sun, 27 Feb 2022 18:05:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=AMsxO2P3weaQAvlcqcwWLnN/LSWoD+a1H1M9VEhhr+w=; b=j5TxDo4q28a7EkdINe9hZaFOYrbEIeY0GW4nGZYiUQGsx3beX0nzXOMizDIng+TyOK JG7IQiZ5cnvYTOrT1SHSXTc3pBt9W3yF20HJwxD7DOOeS+xgT3m/wNIdiQW90Y2EEr70 Qw4eQbrYRbHTT407/zye0HiQOcHA0Rt873EXaGuYzPHSTuWmE7aoW+oZKECPZkxTwh0K mhbYvdTnZBz6xbf5llOmEagVYu4dkhpwIv0O0Dz0eGjf9Ztlw/SVah37NXAveh7F5WZV 0dkpQukXd++9/nsNQTZCMUToqu/UCwCk/YgvH0zs/OkKfwNE3KlmJpRWqzA8D6Msbv6J XVHQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=AMsxO2P3weaQAvlcqcwWLnN/LSWoD+a1H1M9VEhhr+w=; b=U8yt1RCHjKBUQ/Ybx1jrqTaX1TWK/SmLFhIIBtUgNHqJOqB8lSGi1HoBVOLw7SK7IU 4lO2giyq0mSzOxianKDHR9j6sPk4kvk2ZveDmjNFdjzlqCbli4OQKxRr5YibUBzXrBIQ tpZfHmn5dW1xBHgo7QkGjCAXw1cQd6C4Sjw2AvmLhfD/9qKsa1YOXrwODbiR+te/FxiO 4q1vX8pIvKI6CpfvZhQVTFy0wjYBbTl4LdPRw9cv7r1g/eWpU42NKGfXVWDyVTfZJo4n 5fpqEmnNsBTOJeYLAxVYaPx+NN9xNPlsgmHaNRX/YVvevFhpqCM5A4I7Xb+iHff4BDfh ni5Q== X-Gm-Message-State: AOAM533Nds+9WCj0Z0JET+f2gc+QGbaKC6pZJ1gjfgJ/5yb/iFY+Jx+c vuZ48jDxlOyRhSxKCxqF4QRb0b4t+p2fjYI3 X-Google-Smtp-Source: ABdhPJwgsHZDrr3WcZ2QSJ03lyGKdCVA1+Af/7uT9ugUWz2zbbuDjNAzETd/XhFa7GQK7AYk444qsA== X-Received: by 2002:a17:902:f344:b0:151:533b:b6c5 with SMTP id q4-20020a170902f34400b00151533bb6c5mr7453783ple.58.1646013913235; Sun, 27 Feb 2022 18:05:13 -0800 (PST) Received: from [10.11.37.162] ([103.84.139.53]) by smtp.gmail.com with ESMTPSA id j7-20020a056a00130700b004b9f7cd94a4sm10969747pfu.56.2022.02.27.18.05.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 27 Feb 2022 18:05:12 -0800 (PST) Message-ID: <69b0dd44-93ac-fa33-f9c1-6f787185ab47@gmail.com> Date: Mon, 28 Feb 2022 10:05:03 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH] can: usb: fix a possible memory leak in esd_usb2_start_xmit Content-Language: en-US To: Marc Kleine-Budde Cc: wg@grandegger.com, davem@davemloft.net, kuba@kernel.org, stefan.maetje@esd.eu, mailhol.vincent@wanadoo.fr, paskripkin@gmail.com, thunder.leizhen@huawei.com, linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20220225060019.21220-1-hbh25y@gmail.com> <20220225155621.7zmfukra63qcxjo5@pengutronix.de> From: Hangyu Hua In-Reply-To: <20220225155621.7zmfukra63qcxjo5@pengutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi I get it. But this means ems_usb_start_xmit have a redundant dev_kfree_skb beacause can_put_echo_skb delete original skb and can_free_echo_skb delete the cloned skb. While this code is harmless do you think we need to delete it ? Thanks. On 2022/2/25 23:56, Marc Kleine-Budde wrote: > On 25.02.2022 14:00:19, Hangyu Hua wrote: >> As in case of ems_usb_start_xmit, dev_kfree_skb needs to be called when >> usb_submit_urb fails to avoid possible refcount leaks. > > Thanks for your patch. Have you tested that there is actually a mem > leak? Please have a look at the can_free_echo_skb() function that is > called a few lines earlier. > >> Signed-off-by: Hangyu Hua >> --- >> drivers/net/can/usb/esd_usb2.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/net/can/usb/esd_usb2.c b/drivers/net/can/usb/esd_usb2.c >> index 286daaaea0b8..7b5e6c250d00 100644 >> --- a/drivers/net/can/usb/esd_usb2.c >> +++ b/drivers/net/can/usb/esd_usb2.c >> @@ -810,7 +810,7 @@ static netdev_tx_t esd_usb2_start_xmit(struct sk_buff *skb, >> usb_unanchor_urb(urb); >> >> stats->tx_dropped++; >> - >> + dev_kfree_skb(skb); >> if (err == -ENODEV) >> netif_device_detach(netdev); >> else > > regards, > Marc >