From: Michael Ellerman <mpe@ellerman.id.au>
To: Christophe Leroy <christophe.leroy@csgroup.eu>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>, 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: Re: [PATCH 1/3] mm/gup: Use huge_ptep_get() in gup_hugepte()
Date: Thu, 18 Jun 2020 00:14:05 +1000 [thread overview]
Message-ID: <87zh91dbki.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <ffc3714334c3bfaca6f13788ad039e8759ae413f.1592225558.git.christophe.leroy@csgroup.eu>
Christophe Leroy <christophe.leroy@csgroup.eu> writes:
> 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")
I see that commit in older versions of linux-next but not in mainline.
In mainline it seems to be: 9e343b467c70 ("READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses")
I guess it got rebased somewhere along the way.
I fixed it up when applying, and the other two as well.
cheers
> 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
next prev parent reply other threads:[~2020-06-17 14:13 UTC|newest]
Thread overview: 16+ 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 ` [PATCH 1/3] mm/gup: Use huge_ptep_get() in gup_hugepte() Christophe Leroy
2020-06-17 14:14 ` Michael Ellerman [this message]
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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