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Date: Tue, 21 Jul 2026 17:13:51 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Hongfu Li <hongfu.li@linux.dev>
Cc: hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev,
 shakeel.butt@linux.dev, muchun.song@linux.dev, cgroups@vger.kernel.org,
 linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hongfu Li
 <lihongfu@kylinos.cn>
Subject: Re: [PATCH] mm/memcg: check kzalloc_node() return in memcg1_init()
Message-Id: <20260721171351.ec213c13afab38b89c14f849@linux-foundation.org>
In-Reply-To: <20260721100916.76822-1-hongfu.li@linux.dev>
References: <20260721100916.76822-1-hongfu.li@linux.dev>
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On Tue, 21 Jul 2026 18:09:16 +0800 Hongfu Li <hongfu.li@linux.dev> wrote:

> From: Hongfu Li <lihongfu@kylinos.cn>
> 
> Add NULL check for per-node kzalloc_node() allocations in memcg1_init().
> 
> Skip the NUMA node when allocation fails. All users of
> soft_limit_tree.rb_tree_per_node[] safely handle NULL entries, only losing
> soft-limit tracking for that node.
> 
> ...
>
> --- a/mm/memcontrol-v1.c
> +++ b/mm/memcontrol-v1.c
> @@ -2566,6 +2566,8 @@ static int __init memcg1_init(void)
>  		struct mem_cgroup_tree_per_node *rtpn;
>  
>  		rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, node);
> +		if (!rtpn)
> +			continue;
>  
>  		rtpn->rb_root = RB_ROOT;
>  		rtpn->rb_rightmost = NULL;

Thanks.  We assume that mamory allocations cannot fail within __init
code.  Because if they do, the kernel has some ghastly problem and it
cannot possibly run.