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From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Will Deacon <will@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-mm@kvack.org
Subject: [PATCH 1/3] mm/gup: Use huge_ptep_get() in gup_hugepte()
Date: Mon, 15 Jun 2020 12:57:57 +0000 (UTC)	[thread overview]
Message-ID: <ffc3714334c3bfaca6f13788ad039e8759ae413f.1592225558.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1592225557.git.christophe.leroy@csgroup.eu>

gup_hugepte() reads hugepage table entries, it can't read
them directly, huge_ptep_get() must be used.

Fixes: 2ab3a0a02905 ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses")
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 mm/gup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/gup.c b/mm/gup.c
index de9e36262ccb..761df4944ef5 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2425,7 +2425,7 @@ static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
 	if (pte_end < end)
 		end = pte_end;
 
-	pte = READ_ONCE(*ptep);
+	pte = huge_ptep_get(ptep);
 
 	if (!pte_access_permitted(pte, flags & FOLL_WRITE))
 		return 0;
-- 
2.25.0


WARNING: multiple messages have this Message-ID
From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Will Deacon <will@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 1/3] mm/gup: Use huge_ptep_get() in gup_hugepte()
Date: Mon, 15 Jun 2020 12:57:57 +0000 (UTC)	[thread overview]
Message-ID: <ffc3714334c3bfaca6f13788ad039e8759ae413f.1592225558.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1592225557.git.christophe.leroy@csgroup.eu>

gup_hugepte() reads hugepage table entries, it can't read
them directly, huge_ptep_get() must be used.

Fixes: 2ab3a0a02905 ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses")
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 mm/gup.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/gup.c b/mm/gup.c
index de9e36262ccb..761df4944ef5 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2425,7 +2425,7 @@ static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
 	if (pte_end < end)
 		end = pte_end;
 
-	pte = READ_ONCE(*ptep);
+	pte = huge_ptep_get(ptep);
 
 	if (!pte_access_permitted(pte, flags & FOLL_WRITE))
 		return 0;
-- 
2.25.0


  reply	other threads:[~2020-06-15 12:58 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-15 12:57 [PATCH 0/3] Fix build failure with v5.8-rc1 Christophe Leroy
2020-06-15 12:57 ` Christophe Leroy [this message]
2020-06-17 14:14   ` [PATCH 1/3] mm/gup: Use huge_ptep_get() in gup_hugepte() Michael Ellerman
2020-06-15 12:57 ` [PATCH 2/3] mm: Allow arches to provide ptep_get() Christophe Leroy
2020-06-15 12:57 ` [PATCH 3/3] powerpc/8xx: Provide ptep_get() with 16k pages Christophe Leroy
2020-06-15 13:22   ` Peter Zijlstra
2020-06-17 14:21     ` Michael Ellerman
2020-06-17 14:38       ` Peter Zijlstra
2020-06-17 14:45         ` Christophe Leroy
2020-06-18  1:00           ` Michael Ellerman
2020-06-18 14:19             ` Christophe Leroy
2020-06-18  0:58         ` Michael Ellerman
2020-06-18 14:21           ` Christophe Leroy
2020-06-17 10:57 ` [PATCH 0/3] Fix build failure with v5.8-rc1 Will Deacon
2020-06-17 14:13 ` Michael Ellerman
2020-06-18 12:37 ` Michael Ellerman

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