From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 1052911CBA for ; Mon, 10 Mar 2025 14:04:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741615477; cv=none; b=QXRXqKJQQF4bF9r5y1YHnbiXAe2DmlVBHEHQXPXXqPyUZwmGZ4lnD6osU+sUw3o9hOkLE3VGxZG4auXsELtW+eQhBDAcqr+QG5/0Bcl0B9KWdQoZqsk4gOfeqLyUzNLnqaBEIIkdhnt3Vz/POGVHgMtdHqjl4+0SkBhHc4PlxEQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741615477; c=relaxed/simple; bh=Asv4npWWTEfAL3DnohBAL7RsGf+eA4DlAlBf8mggrHI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=AAJHULZqeZml0nWTehHVT5ittwQTuYxhlqtETkSkigRry/rAjyGhke+KxH89PdiFPXk9KuuY8DGT5xJddKBcrBMRiHaSPsnDatUsmszyWa9tTBpsWc8lt102xNGXh3YvDZa9ps0O4yJSbG3HUro1UIflKv7n3O9PBNfDaXiRq2Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E22F916F2; Mon, 10 Mar 2025 07:04:45 -0700 (PDT) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.27]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id B46123F673; Mon, 10 Mar 2025 07:04:33 -0700 (PDT) From: Ryan Roberts To: Andrew Morton , Lorenzo Stoakes Cc: Ryan Roberts , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v1] mm: use ptep_get() instead of directly dereferencing pte_t* Date: Mon, 10 Mar 2025 14:04:17 +0000 Message-ID: <20250310140418.1737409-1-ryan.roberts@arm.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit It is best practice for all pte accesses to go via the arch helpers, to ensure non-torn values and to allow the arch to intervene where needed (contpte for arm64 for example). While in this case it was probably safe to directly dereference, let's tidy it up for consistency. Signed-off-by: Ryan Roberts --- mm/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/migrate.c b/mm/migrate.c index 22e270f727ed..33a22c2d6b20 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -202,7 +202,7 @@ static bool try_to_map_unused_to_zeropage(struct page_vma_mapped_walk *pvmw, return false; VM_BUG_ON_PAGE(!PageAnon(page), page); VM_BUG_ON_PAGE(!PageLocked(page), page); - VM_BUG_ON_PAGE(pte_present(*pvmw->pte), page); + VM_BUG_ON_PAGE(pte_present(ptep_get(pvmw->pte)), page); if (folio_test_mlocked(folio) || (pvmw->vma->vm_flags & VM_LOCKED) || mm_forbids_zeropage(pvmw->vma->vm_mm)) -- 2.43.0