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Date: Thu, 29 Jan 2026 15:50:10 -0800
From: Jakub Kicinski <kuba@kernel.org>
To: Ratheesh Kannoth <rkannoth@marvell.com>
Cc: <edumazet@google.com>, <sumang@marvell.com>,
 <linux-kernel@vger.kernel.org>, <sbhatta@marvell.com>,
 <davem@davemloft.net>, <netdev@vger.kernel.org>, <pabeni@redhat.com>,
 <andrew+netdev@lunn.ch>, <sgoutham@marvell.com>
Subject: Re: [net-next,v6,01/13] octeontx2-af: npc: cn20k: Index management
Message-ID: <20260129155010.64297c67@kernel.org>
In-Reply-To: <aXrutHgsKEuJUlGK@rkannoth-OptiPlex-7090>
References: <20260128071235.3577206-2-rkannoth@marvell.com>
	<20260129051301.376533-1-kuba@kernel.org>
	<aXrutHgsKEuJUlGK@rkannoth-OptiPlex-7090>
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On Thu, 29 Jan 2026 10:53:00 +0530 Ratheesh Kannoth wrote:
> > When cnt is odd, the final loop iteration has i = cnt - 1, which means
> > subbank_srch_order[i + 1] writes to index cnt, which is out of bounds.
> >
> > For example with cnt = 5, the loop iterates with i = 0, 2, 4. At i = 4,
> > the array access subbank_srch_order[5] overflows the allocated array of
> > 5 elements.
> >
> > While CN20K hardware typically has 32 subbanks (even), the value is read
> > from a hardware register at npc_priv_init() without validation beyond
> > checking for zero. Could this lead to memory corruption if the hardware
> > reports an odd subbank count?  
> subbank count is 16 or 8, depending on SoC variant. i will add a WARN check on
> odd ?

Or just a comment may work to prevent the false positive