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 74ADDC433F5 for ; Mon, 11 Apr 2022 10:13:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345169AbiDKKPR (ORCPT ); Mon, 11 Apr 2022 06:15:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239505AbiDKKPP (ORCPT ); Mon, 11 Apr 2022 06:15:15 -0400 Received: from mail-wm1-f48.google.com (mail-wm1-f48.google.com [209.85.128.48]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3707441F95 for ; Mon, 11 Apr 2022 03:13:02 -0700 (PDT) Received: by mail-wm1-f48.google.com with SMTP id l62-20020a1c2541000000b0038e4570af2fso9690206wml.5 for ; Mon, 11 Apr 2022 03:13:02 -0700 (PDT) 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=NIpP1nx9/f18tnpNY46mhDB5G980D7IcTknlfdST6Ik=; b=40iDGOwd0uNRqsZJsB0kHXwHcm+aH8RHI8lTzYAq+PsbNFCnJXzS8Plte1jpCKGFLA o0WUml7rKdTRuPDw5v5GrytP9dfKh7jBSHPRqehs8fPQii/Xtb8BbZtB+Su3NMDQtBTK 0DiJUp8s43zIjB6KpVaAIgww5uQjiiUlDd7865Wdfr0RtxIv6fv4jei+Y+d0WvDoV6c/ f5hYBNzDcMlHXCxaj8WFdgFnmUCXQz7NZUMEWo7ieZIGS0IT5PYT1TIqQUmhYfNB5JRk Umxow1YIr4MtzErhumjTfTX91o/WUKN6RhoLlt1hnC+EsQqZhwfIiBFjvEpQoRMkngnm ourQ== X-Gm-Message-State: AOAM533ofv2PUJU4NYu0wQwzq3mvBXov5UtMlq62HmH6YMmC9E3VGY2h oUnpa85spaKRDFjcInQhCVU= X-Google-Smtp-Source: ABdhPJx/5SyYwGZ1hGDiJt3ggQIe26BvClG7jZAjo8qrfDRoJzUZM3DTKzv+0wS3h3x74UWwi90TRg== X-Received: by 2002:a1c:7518:0:b0:381:c77:ceec with SMTP id o24-20020a1c7518000000b003810c77ceecmr28458283wmc.57.1649671980640; Mon, 11 Apr 2022 03:13:00 -0700 (PDT) Received: from [192.168.1.49] (185-219-167-24-static.vivo.cz. [185.219.167.24]) by smtp.gmail.com with ESMTPSA id l6-20020a1c2506000000b0038e6fe8e8d8sm22732493wml.5.2022.04.11.03.12.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 11 Apr 2022 03:12:59 -0700 (PDT) Message-ID: Date: Mon, 11 Apr 2022 12:12:59 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH] tty: synclink_gt: Fix null-pointer-dereference in slgt_clean() Content-Language: en-US To: Zheyu Ma , gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org References: <20220410114814.3920474-1-zheyuma97@gmail.com> From: Jiri Slaby In-Reply-To: <20220410114814.3920474-1-zheyuma97@gmail.com> 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 On 10. 04. 22, 13:48, Zheyu Ma wrote: > When the driver fails at alloc_hdlcdev(), and then we remove the driver > module, we will get the following splat: > > [ 25.065966] general protection fault, probably for non-canonical address 0xdffffc0000000182: 0000 [#1] PREEMPT SMP KASAN PTI > [ 25.066914] KASAN: null-ptr-deref in range [0x0000000000000c10-0x0000000000000c17] > [ 25.069262] RIP: 0010:detach_hdlc_protocol+0x2a/0x3e0 > [ 25.077709] Call Trace: > [ 25.077924] > [ 25.078108] unregister_hdlc_device+0x16/0x30 > [ 25.078481] slgt_cleanup+0x157/0x9f0 [synclink_gt] > > Fix this by checking whether the 'info->netdev' is a null pointer first. Hi, LGTM Reviewed-by: Jiri Slaby Out of curiosity, do you use the driver, or you only do some static analysis? > Signed-off-by: Zheyu Ma > --- > drivers/tty/synclink_gt.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c > index 25c558e65ece..9bc2a9265277 100644 > --- a/drivers/tty/synclink_gt.c > +++ b/drivers/tty/synclink_gt.c > @@ -1746,6 +1746,8 @@ static int hdlcdev_init(struct slgt_info *info) > */ > static void hdlcdev_exit(struct slgt_info *info) > { > + if (!info->netdev) > + return; > unregister_hdlc_device(info->netdev); > free_netdev(info->netdev); > info->netdev = NULL; -- js suse labs