Re: [PATCH] net: atlantic: fix fragment overflow handling in RX path

[Jiefeng]

I have used git send-email to send my code.

As for the patch --The aquantia/atlantic driver supports a maximum of
AQ_CFG_SKB_FRAGS_MAX (32U) fragments, while the kernel limits the
maximum number of fragments to MAX_SKB_FRAGS (17).

Jakub Kicinski <kuba@xxxxxxxxxx> 于2025年11月18日周二 08:42写道：
>
> On Mon, 17 Nov 2025 19:38:54 +0800 Jiefeng wrote:
> > From f78a25e62b4a0155beee0449536ba419feeddb75 Mon Sep 17 00:00:00 2001
> > From: Jiefeng Zhang <jiefeng.z.zhang@xxxxxxxxx>
> > Date: Mon, 17 Nov 2025 16:17:37 +0800
> > Subject: [PATCH] net: atlantic: fix fragment overflow handling in RX path
> >
> > The atlantic driver can receive packets with more than MAX_SKB_FRAGS (17)
> > fragments when handling large multi-descriptor packets. This causes an
> > out-of-bounds write in skb_add_rx_frag_netmem() leading to kernel panic.
> >
> > The issue occurs because the driver doesn't check the total number of
> > fragments before calling skb_add_rx_frag(). When a packet requires more
> > than MAX_SKB_FRAGS fragments, the fragment index exceeds the array bounds.
> >
> > Add a check in __aq_ring_rx_clean() to ensure the total number of fragments
> > (including the initial header fragment and subsequent descriptor fragments)
> > does not exceed MAX_SKB_FRAGS. If it does, drop the packet gracefully
> > and increment the error counter.
>
> This submissions is not formatted correctly. Use git or b4 to send your
> code. Please also make sure you read:
> https://www.kernel.org/doc/html/next/process/maintainer-netdev.html
>
> As for the patch -- what's the frag size the driver uses? If it's
> larger than max_mtu / 16 the overflow is impossible.