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	Thu, 28 May 2026 19:37:31 +0000
Date: Thu, 28 May 2026 20:37:30 +0100
From: Matthew Wilcox <willy@infradead.org>
To: Yury Norov <ynorov@nvidia.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@kernel.org>, Zi Yan <ziy@nvidia.com>,
	Matthew Brost <matthew.brost@intel.com>,
	Joshua Hahn <joshua.hahnjy@gmail.com>, Rakie Kim <rakie.kim@sk.com>,
	Byungchul Park <byungchul@sk.com>,
	Gregory Price <gourry@gourry.net>,
	Ying Huang <ying.huang@linux.alibaba.com>,
	Alistair Popple <apopple@nvidia.com>, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org,
	Farhad Alemi <farhad.alemi@berkeley.edu>,
	Waiman Long <longman@redhat.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	cgroups@vger.kernel.org
Subject: Re: [PATCH] mm: don't allow empty relative nodemask in
 mpol_relative_nodemask()
Message-ID: <ahiZeqgwUxqAOPiG@casper.infradead.org>
References: <20260528190337.878027-1-ynorov@nvidia.com>
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In-Reply-To: <20260528190337.878027-1-ynorov@nvidia.com>

On Thu, May 28, 2026 at 03:03:37PM -0400, Yury Norov wrote:
>  static void mpol_relative_nodemask(nodemask_t *ret, const nodemask_t *orig,
          ^^^^

>  				   const nodemask_t *rel)
>  {
> +	unsigned int w = nodes_weight(*rel);
>  	nodemask_t tmp;
> -	nodes_fold(tmp, *orig, nodes_weight(*rel));
> +
> +	if (w == 0)
> +		return -EINVAL;

... this doesn't even compile.