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Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
Date:   Wed, 18 Oct 2023 14:44:52 +0200
From:   Ingo Molnar <mingo@kernel.org>
To:     Qi Zheng <zhengqi.arch@bytedance.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Mike Rapoport <rppt@kernel.org>,
        David Hildenbrand <david@redhat.com>,
        Michal Hocko <mhocko@suse.com>,
        Andrew Morton <akpm@linux-foundation.org>, x86@kernel.org,
        Andy Lutomirski <luto@kernel.org>,
        Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH v2] x86/mm: Drop 4MB restriction on minimal NUMA node
 memory size
Message-ID: <ZS/TRNf02Un8IOTK@gmail.com>
References: <20231017062215.171670-1-rppt@kernel.org>
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 <605cc166-e731-e7d1-25d7-b6797a802e6f@bytedance.com>
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* Qi Zheng <zhengqi.arch@bytedance.com> wrote:

> > While I agree with dropping the limitation, and I agree that 
> > 9391a3f9c7f1 should have provided more of a justification, I believe a 
> > core MM fix is in order as well, for it to not crash. [ If it's fixed 
> > upstream already, please reference the relevant commit ID. ]
> 
> Agree. I posted a fixed patchset[1] before, maybe we can reconsider it. 
> :)
> 
> [1]. https://lore.kernel.org/lkml/20230215152412.13368-1-zhengqi.arch@bytedance.com/
> 
> For memoryless node, this patchset skip it and fallback to other nodes
> when build its zonelists.

Mind resubmitting that to the MM folks, with the NULL dereference crash 
mentioned prominently? Feel free to Cc: me.

Fixing hypothetical robustness problems is good, fixing specific crashes is 
better. :-)

Thanks,

	Ingo