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From: Oscar Salvador <osalvador@suse.com>
Date: Mon, 3 Jun 2024 19:53:55 +0200
To: David Hildenbrand <david@redhat.com>
Cc: Anastasia Belova <abelova@astralinux.ru>,
	Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, lvc-project@linuxtesting.org
Subject: Re: [PATCH] mm/memory_hotplug: prevent accessing by index=-1
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 <3c2b1b1e-c9b3-442e-8f7b-5c7518d3fbdb@redhat.com>
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On Mon, Jun 03, 2024 at 06:07:39PM +0200, David Hildenbrand wrote:
> pgdat is never dereferenced when "nid == NUMA_NO_NODE".

Right.

> NODE_DATA is defined as
> 
> arch/arm64/include/asm/mmzone.h:#define NODE_DATA(nid)          (node_data[(nid)])
> arch/loongarch/include/asm/mmzone.h:#define NODE_DATA(nid)      (node_data[(nid)])
> arch/mips/include/asm/mach-ip27/mmzone.h:#define NODE_DATA(n)           (&__node_data[(n)]->pglist)

All look fine, but mips.

Is it not dangerous to try to derefence &__node_data[-1]->pglist?


-- 
Oscar Salvador
SUSE Labs