From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Sasha Levin <sashal@kernel.org>,
linux-s390@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 10/17] s390/mm: fix set_huge_pte_at() for empty ptes
Date: Thu, 28 May 2020 07:57:17 -0400 [thread overview]
Message-ID: <20200528115724.1406376-10-sashal@kernel.org> (raw)
In-Reply-To: <20200528115724.1406376-1-sashal@kernel.org>
From: Gerald Schaefer <gerald.schaefer@de.ibm.com>
[ Upstream commit ac8372f3b4e41015549b331a4f350224661e7fc6 ]
On s390, the layout of normal and large ptes (i.e. pmds/puds) differs.
Therefore, set_huge_pte_at() does a conversion from a normal pte to
the corresponding large pmd/pud. So, when converting an empty pte, this
should result in an empty pmd/pud, which would return true for
pmd/pud_none().
However, after conversion we also mark the pmd/pud as large, and
therefore present. For empty ptes, this will result in an empty pmd/pud
that is also marked as large, and pmd/pud_none() would not return true.
There is currently no issue with this behaviour, as set_huge_pte_at()
does not seem to be called for empty ptes. It would be valid though, so
let's fix this by not marking empty ptes as large in set_huge_pte_at().
This was found by testing a patch from from Anshuman Khandual, which is
currently discussed on LKML ("mm/debug: Add more arch page table helper
tests").
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/mm/hugetlbpage.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
index 5674710a4841..7dfae86afa47 100644
--- a/arch/s390/mm/hugetlbpage.c
+++ b/arch/s390/mm/hugetlbpage.c
@@ -159,10 +159,13 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
rste &= ~_SEGMENT_ENTRY_NOEXEC;
/* Set correct table type for 2G hugepages */
- if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
- rste |= _REGION_ENTRY_TYPE_R3 | _REGION3_ENTRY_LARGE;
- else
+ if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) {
+ if (likely(pte_present(pte)))
+ rste |= _REGION3_ENTRY_LARGE;
+ rste |= _REGION_ENTRY_TYPE_R3;
+ } else if (likely(pte_present(pte)))
rste |= _SEGMENT_ENTRY_LARGE;
+
clear_huge_pte_skeys(mm, rste);
pte_val(*ptep) = rste;
}
--
2.25.1
next prev parent reply other threads:[~2020-05-28 12:02 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-28 11:57 [PATCH AUTOSEL 4.19 01/17] ARC: Fix ICCM & DCCM runtime size checks Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 02/17] ARC: [plat-eznps]: Restrict to CONFIG_ISA_ARCOMPACT Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 03/17] evm: Fix RCU list related warnings Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 04/17] i2c: altera: Fix race between xfer_msg and isr thread Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 05/17] net sched: fix reporting the first-time use timestamp Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 06/17] x86/mmiotrace: Use cpumask_available() for cpumask_var_t variables Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 07/17] net: bmac: Fix read of MAC address from ROM Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 08/17] r8152: support additional Microsoft Surface Ethernet Adapter variant Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 09/17] drm/edid: Add Oculus Rift S to non-desktop list Sasha Levin
2020-05-28 11:57 ` Sasha Levin [this message]
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 11/17] null_blk: return error for invalid zone size Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 12/17] net/ethernet/freescale: rework quiesce/activate for ucc_geth Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 13/17] net: ethernet: stmmac: Enable interface clocks on probe for IPQ806x Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 14/17] net: sun: fix missing release regions in cas_init_one() Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 15/17] net/mlx5: Add command entry handling completion Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 16/17] net/mlx4_core: fix a memory leak bug Sasha Levin
2020-05-28 11:57 ` [PATCH AUTOSEL 4.19 17/17] net: smsc911x: Fix runtime PM imbalance on error Sasha Levin
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