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From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Heiko Carstens <hca@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Sven Schnelle <svens@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: linux-s390@vger.kernel.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] s390/mm: Remove folio handling for secure storage access exceptions
Date: Thu, 16 Jul 2026 16:19:34 +0200	[thread overview]
Message-ID: <d54653cc-caf4-4e87-a23d-40aa6d53187b@kernel.org> (raw)
In-Reply-To: <20260716141436.2125703-4-hca@linux.ibm.com>

On 7/16/26 16:14, Heiko Carstens wrote:
> Remove folio handling for secure storage access exceptions that happen
> via the kernel mapping. Using folio_try_get() for exceptions via the
> kernel mapping is racy: for example such an exception may happen on one
> CPU, while a different CPU frees the corresponding page. Subsequently the
> page can be part of a folio of different size, before the faulting CPU
> executes folio_try_get(). This may lead to data corruption.

Right, that's why one would have to re-verify whether the page is still part of
the folio afterwards.

-- 
Cheers,

David

  reply	other threads:[~2026-07-16 14:19 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-07-16 14:14 [PATCH 0/4] s390: Reintroduce support for DCACHE_WORD_ACCESS Heiko Carstens
2026-07-16 14:14 ` [PATCH 1/4] KVM: s390: pv: Use VM_SPARSE area for guest variable storage area Heiko Carstens
2026-07-16 14:33   ` sashiko-bot
2026-07-16 14:14 ` [PATCH 2/4] s390/mm: Fix handling of secure storage access exceptions in vmalloc area Heiko Carstens
2026-07-16 14:14 ` [PATCH 3/4] s390/mm: Remove folio handling for secure storage access exceptions Heiko Carstens
2026-07-16 14:19   ` David Hildenbrand (Arm) [this message]
2026-07-16 14:14 ` [PATCH 4/4] s390: Add support for DCACHE_WORD_ACCESS (again) Heiko Carstens

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