linux-kernel - [PATCH 4.14 015/143] arm64: hugetlb: Fix handling of young ptes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20181102182858.309982426@linuxfoundation.org>
Date:   Fri,  2 Nov 2018 19:33:20 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Steve Capper <steve.capper@....com>,
        Will Deacon <will.deacon@....com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.14 015/143] arm64: hugetlb: Fix handling of young ptes

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 469ed9d823b7d240d6b9574f061ded7c3834c167 ]

In the contiguous bit hugetlb break-before-make code we assume that all
hugetlb pages are young.

In fact, remove_migration_pte is able to place an old hugetlb pte so
this assumption is not valid.

This patch fixes the contiguous hugetlb scanning code to preserve young
ptes.

Fixes: d8bdcff28764 ("arm64: hugetlb: Add break-before-make logic for contiguous entries")
Signed-off-by: Steve Capper <steve.capper@....com>
Signed-off-by: Will Deacon <will.deacon@....com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/arm64/mm/hugetlbpage.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 6cb0fa92a651..9f6ae9686dac 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -118,11 +118,14 @@ static pte_t get_clear_flush(struct mm_struct *mm,
 
 		/*
 		 * If HW_AFDBM is enabled, then the HW could turn on
-		 * the dirty bit for any page in the set, so check
-		 * them all.  All hugetlb entries are already young.
+		 * the dirty or accessed bit for any page in the set,
+		 * so check them all.
 		 */
 		if (pte_dirty(pte))
 			orig_pte = pte_mkdirty(orig_pte);
+
+		if (pte_young(pte))
+			orig_pte = pte_mkyoung(orig_pte);
 	}
 
 	if (valid)
@@ -347,10 +350,13 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 	if (!pte_same(orig_pte, pte))
 		changed = 1;
 
-	/* Make sure we don't lose the dirty state */
+	/* Make sure we don't lose the dirty or young state */
 	if (pte_dirty(orig_pte))
 		pte = pte_mkdirty(pte);
 
+	if (pte_young(orig_pte))
+		pte = pte_mkyoung(pte);
+
 	hugeprot = pte_pgprot(pte);
 	for (i = 0; i < ncontig; i++, ptep++, addr += pgsize, pfn += dpfn)
 		set_pte_at(vma->vm_mm, addr, ptep, pfn_pte(pfn, hugeprot));
-- 
2.17.1