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From: Yang Shi <yang@os.amperecomputing.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: LAK <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [Question] mprotect() can't clear PROT_MTE
Date: Wed, 29 Oct 2025 15:41:17 -0700	[thread overview]
Message-ID: <04ea9978-e6aa-4498-b899-76d56e19b084@os.amperecomputing.com> (raw)

Hi Catalin,

Our customers have usecase to untag memory w/o unmapping it, but 
mprotect can't do it. It seems like an intended behavior because I saw 
MTE doc explicitly says PROT_MTE flags can't be cleared by mprotect().
But I don't see why mprotect() can't do it if I don't miss anything. So 
I'd like to know why it behaves in this way.

unmap + mmap or mmap(MAP_FIXED) can do the trick, but it is not feasible 
for anonymous mapping because unamp will wipe all the data.

Thanks,
Yang


             reply	other threads:[~2025-10-29 22:41 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-29 22:41 Yang Shi [this message]
2025-10-31 18:48 ` Catalin Marinas
2025-11-03 18:22   ` Yang Shi

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