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From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Martin Weiser <martin.weiser@allegro-packets.com>,
	Ciara Loftus <ciara.loftus@intel.com>,
	Qi Zhang <qi.z.zhang@intel.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] net/af_xdp: fix integer overflow in umem size calculation
Date: Fri, 30 Oct 2020 15:01:34 +0000
Message-ID: <5dcf837b-3a8c-866e-c22e-78035de9d3dc@intel.com> (raw)
In-Reply-To: <c5e85c73-ba24-bbf8-b1c9-9b1656919c61@allegro-packets.com>

On 10/29/2020 12:41 PM, Martin Weiser wrote:
> Hi,
> 
> the reason why I stumbled across this issue is because I was getting
> inconsistent errors during interface rx queue setup.
> We generally use quite large mempools and it looks like the umem setup
> fails for larger sizes. But because of the integer overflow the
> umem_size sometimes became small enough to let the umem setup work, so
> it was not immediately obvious what was going wrong.
> 
> It seems that the umem setup (specifically the setsockopt call with
> XDP_UMEM_REG in libbpf's xsk_umem__create_v0_0_4()) fails with any
> length greater than 2GB and returns ENOMEM. This at least happens on our
> systems with kernel 5.8.
> Are you aware of any such kernel-side limitation? This basically makes
> af_xdp unusable with mempools larger than 2GB.
> 
> Best regards,
> Martin
> 
> 
> Am 29.10.20 um 12:25 schrieb Martin Weiser:
>> The multiplication of two u32 integers may cause an overflow with large
>> mempool sizes.
>>
>> Fixes: 74b46340e2d4 ("net/af_xdp: support shared UMEM")
>> Cc: ciara.loftus@intel.com
>>
>> Signed-off-by: Martin Weiser <martin.weiser@allegro-packets.com>

Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>

Applied to dpdk-next-net/main, thanks.

      reply	other threads:[~2020-10-30 15:01 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-29 11:25 Martin Weiser
2020-10-29 12:41 ` Martin Weiser
2020-10-30 15:01   ` Ferruh Yigit [this message]

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