linux-kernel - Re: [PATCH 2/3] proc: kpagecount: use snapshot

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Message-ID: <3ee3adfc-5efc-43dd-9c75-23564fade7b3@amd.com>
Date: Wed, 2 Jul 2025 11:55:05 +0530
From: Shivank Garg <shivankg@....com>
To: Luiz Capitulino <luizcap@...hat.com>, david@...hat.com,
 willy@...radead.org
Cc: akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
 linux-mm@...ck.org, lcapitulino@...il.com
Subject: Re: [PATCH 2/3] proc: kpagecount: use snapshot_page()



On 6/26/2025 11:46 PM, Luiz Capitulino wrote:
> Currently, the call to folio_precise_page_mapcount() from kpage_read()
> can race with a folio split. When the race happens we trigger a
> VM_BUG_ON_FOLIO() in folio_entire_mapcount() (see splat below).
> 
> This commit fixes this race by using snapshot_page() so that we
> retreive the folio mapcount using a folio snapshot.

s/retreive/retrieve/
checkpatch.pl would have flagged this.

Rest looks good to me.

Thanks,
Shivank