From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
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 7BACFC04A6A
	for <linux-kernel@archiver.kernel.org>; Wed,  2 Aug 2023 03:19:05 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S231987AbjHBDTC (ORCPT <rfc822;linux-kernel@archiver.kernel.org>);
        Tue, 1 Aug 2023 23:19:02 -0400
Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55892 "EHLO
        lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S231953AbjHBDSu (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Tue, 1 Aug 2023 23:18:50 -0400
Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217])
        by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF0961724
        for <linux-kernel@vger.kernel.org>; Tue,  1 Aug 2023 20:18:49 -0700 (PDT)
Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140])
        (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)
         key-exchange X25519 server-signature RSA-PSS (2048 bits))
        (No client certificate requested)
        by dfw.source.kernel.org (Postfix) with ESMTPS id 7C1D56179A
        for <linux-kernel@vger.kernel.org>; Wed,  2 Aug 2023 03:18:49 +0000 (UTC)
Received: by smtp.kernel.org (Postfix) with ESMTPSA id 87C2BC433C9;
        Wed,  2 Aug 2023 03:18:48 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;
        s=k20201202; t=1690946328;
        bh=pPUw7iVxQvIYg97/YCPzTavNzCKbFieabBAhT15a2Uo=;
        h=Date:Subject:To:Cc:References:From:In-Reply-To:From;
        b=bkcncHKz/50NbkYBuFySUwMr+ehRZ3ht7OWpcR8GWtU9m5OJRSsRdhOZP45x0rMiD
         lyx9oHODYj1kNIMtZbddO5jGYdkgXmN1COwQMNkWLN4keMu4QdMN0RHqdPT7Sw3h2S
         8sw2tGvk5fH6inIRlp4Za54mZBfkfUTJizanswHdHaemnbxhroj9TkO1PS4gkVr3Jx
         knPz4E1dqyrHQVD38G0/LL6vyuxJIXJxePRJO5wvLBqeKNrFqEK83J7nxMFRCfFc/x
         1Fj9/5wRTGf13jfSNeHUBBWzT4cvZiFyuMndA0R43CY0RKi5Zfk1cQwBQpbL/1Njwk
         8ORqcl2mqQHyA==
Message-ID: <cbefa473-2d48-5df9-f773-8bb6bdcd6be1@kernel.org>
Date:   Tue, 1 Aug 2023 21:18:47 -0600
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0)
 Gecko/20100101 Thunderbird/102.13.0
Subject: Re: [PATCH v3] ip6mr: Fix skb_under_panic in ip6mr_cache_report()
Content-Language: en-US
To:     Jakub Kicinski <kuba@kernel.org>,
        YueHaibing <yuehaibing@huawei.com>
Cc:     Eric Dumazet <edumazet@google.com>, davem@davemloft.net,
        pabeni@redhat.com, yoshfuji@linux-ipv6.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, simon.horman@corigine.com
References: <20230801064318.34408-1-yuehaibing@huawei.com>
 <CANn89iJO44CiUjftDZHEjOCy5Q3-PDB12uWTkrbA5JJNXMoeDA@mail.gmail.com>
 <20230801131146.51a9aaf3@kernel.org>
 <0e3e2d6f-0e8d-ccb4-0750-928a568ccaaf@kernel.org>
 <cad2b715-14fc-8424-f85d-b5391e0110dc@huawei.com>
 <20230801191058.0664b1b8@kernel.org>
From:   David Ahern <dsahern@kernel.org>
In-Reply-To: <20230801191058.0664b1b8@kernel.org>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 8/1/23 8:10 PM, Jakub Kicinski wrote:
> On Wed, 2 Aug 2023 09:28:31 +0800 YueHaibing wrote:
>>> that pattern shows up a few times:  
>>
>> Ok, I will test and fix these if any.
> 
> Thanks, we may also want to add a 
>   DEBUG_NET_WARN_ON_ONCE(len > INT_MAX)
> in skb_push() but perhaps that's an overkill.
> Most of those cases are probably legit (skb_.*_offset()
> can well be negative if headers were already pulled).

Yea, a lot of those could be legit, so it would be best to have a test
case that shows it can be triggered and then any patch fixes it.