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Mon, 02 Mar 2026 01:02:10 -0800 (PST) Date: Mon, 2 Mar 2026 09:02:10 +0000 From: Wei Yang To: "David Hildenbrand (Arm)" Cc: Wei Yang , Zi Yan , Linux MM Subject: Re: A potential refcount issue during __folio_split Message-ID: <20260302090210.mssx5sdq7qrjr2yv@master> Reply-To: Wei Yang References: <20260222010425.gbsjzhrew3pg4qrw@master> <20260222010708.uohpmddmzaa4i4ic@master> <6346656B-7518-4A55-8DEF-C2E975714C8B@nvidia.com> <3e22afe6-ecf7-4180-9287-c48fea7b8be1@kernel.org> <20260223115948.sbylmtqhznmabcth@master> <097A507A-C60A-47AF-9590-1D6CF712B1FE@nvidia.com> <20260301235902.duqcfrymearzrpds@master> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) X-Stat-Signature: 61zn7wu7jnb13w1nxopjnodkgd46exu7 X-Rspam-User: X-Rspamd-Queue-Id: A4605160005 X-Rspamd-Server: rspam12 X-HE-Tag: 1772442133-728107 X-HE-Meta: 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 1IEoFY4F 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Mar 02, 2026 at 09:01:05AM +0100, David Hildenbrand (Arm) wrote: >On 3/2/26 00:59, Wei Yang wrote: >> On Mon, Feb 23, 2026 at 11:00:01PM -0500, Zi Yan wrote: >>> On 23 Feb 2026, at 6:59, Wei Yang wrote: >>> >>>> >>>> Missed this. Agree. >>>> >>>> >>>> I am afraid it would be complicated? >>>> >>>> Well, we don't have this usecase now, could decide it when we do need it. >>> >>> The patch below should work, but for now, since we do not have any user, >>> it is better to update the comment and add a check to make sure @lock_at >>> always points to the head page if @list is not NULL. >>> >> >> Hi, Zi Yan >> >> Just want to confirm what we prefer to do now. We have three options: >> >> 1) update comment and a check on @lock_at >> 2) fix it as you proposed below >> 3) do nothing for now > >I'd go with 3). > Got it. -- Wei Yang Help you, Help me