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Date:   Tue, 1 Aug 2023 21:18:47 -0600
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Subject: Re: [PATCH v3] ip6mr: Fix skb_under_panic in ip6mr_cache_report()
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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>
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From:   David Ahern <dsahern@kernel.org>
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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.