From: "David Hildenbrand (Arm)" <david@kernel.org>
To: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>,
Vernon Yang <vernon2gm@gmail.com>
Cc: akpm@linux-foundation.org, nico.pache@linux.dev,
ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org,
lance.yang@linux.dev, usama.arif@linux.dev, zokeefe@google.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Vernon Yang <yanglincheng@kylinos.cn>,
stable@vger.kernel.org
Subject: Re: [PATCH v2 1/3] mm: khugepaged: fix swap entry value to folio_pfn()
Date: Mon, 17 Aug 2026 18:19:16 +0200 [thread overview]
Message-ID: <cf1d271c-f002-427a-a843-00a1fbc59251@kernel.org> (raw)
In-Reply-To: <aoMs79VDCnYvA9S7@lucifer>
> I mean maybe better to just reduce this to something like:
>
> /* folio is NULL unless exited early. */
> trace_mm_khugepaged_scan_file(mm,
> (!folio || xa_is_value(folio)) ? -1 : folio_pfn(folio),
> file, present, swap, result);
>
> As the least invasive way of fixing the trace + limiting the contageon?
I raised that using a folio after dropping relevant refs+locks is in general an
anti-pattern (IOW wrong if folios can just get split afterwards and are suddenly
no longer folios).
I'd like us to avoid that where possible (and suspect Willy will thank us later ;) )
Isn't there some minimal way to just calculate the pfn once we obtain a folio? I
was assuming that there should be an easier way to do that.
--
Cheers,
David
next prev parent reply other threads:[~2026-08-17 16:19 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-15 5:19 [PATCH v2 0/3] mm: khugepaged: fix tracepoint UAF Vernon Yang
2026-08-15 5:19 ` [PATCH v2 1/3] mm: khugepaged: fix swap entry value to folio_pfn() Vernon Yang
2026-08-17 16:10 ` Lorenzo Stoakes (ARM)
2026-08-17 16:19 ` David Hildenbrand (Arm) [this message]
2026-08-17 16:24 ` Lorenzo Stoakes (ARM)
2026-08-17 16:23 ` Lorenzo Stoakes (ARM)
2026-08-15 5:19 ` [PATCH v2 2/3] mm: khugepaged: fix folio is used after pte_unmap_unlock() Vernon Yang
2026-08-17 16:11 ` Lorenzo Stoakes (ARM)
2026-08-17 16:20 ` David Hildenbrand (Arm)
2026-08-17 16:29 ` Lorenzo Stoakes (ARM)
2026-08-17 16:33 ` Lorenzo Stoakes
2026-08-15 5:19 ` [PATCH v2 3/3] mm: khugepaged: fix folio is used after folio_put/unlock() Vernon Yang
2026-08-15 17:44 ` [PATCH v2 0/3] mm: khugepaged: fix tracepoint UAF Lance Yang
2026-08-15 18:16 ` Lance Yang
2026-08-17 2:25 ` Baolin Wang
2026-08-17 2:53 ` Lance Yang
2026-08-17 7:24 ` Baolin Wang
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