From: Mel Gorman <mgorman@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>, Hugh Dickins <hughd@google.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>, Ingo Molnar <mingo@redhat.com>,
Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>,
Sasha Levin <sasha.levin@oracle.com>,
LinuxPPC-dev <linuxppc-dev@lists.ozlabs.org>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>,
Mel Gorman <mgorman@suse.de>
Subject: [PATCH 09/10] mm: numa: Add paranoid check around pte_protnone_numa
Date: Mon, 5 Jan 2015 10:54:10 +0000 [thread overview]
Message-ID: <1420455251-13644-10-git-send-email-mgorman@suse.de> (raw)
In-Reply-To: <1420455251-13644-1-git-send-email-mgorman@suse.de>
pte_protnone_numa is only safe to use after VMA checks for PROT_NONE are
complete. Treating a real PROT_NONE PTE as a NUMA hinting fault is going
to result in strangeness so add a check for it. BUG_ON looks like overkill
but if this is hit then it's a serious bug that could result in corruption
so do not even try recovering. It would have been more comprehensive to
check VMA flags in pte_protnone_numa but it would have made the API ugly
just for a debugging check.
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/huge_memory.c | 3 +++
mm/memory.c | 3 +++
2 files changed, 6 insertions(+)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index ad2a3ee..8546654 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1273,6 +1273,9 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
bool migrated = false;
int flags = 0;
+ /* A PROT_NONE fault should not end up here */
+ BUG_ON(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)));
+
ptl = pmd_lock(mm, pmdp);
if (unlikely(!pmd_same(pmd, *pmdp)))
goto out_unlock;
diff --git a/mm/memory.c b/mm/memory.c
index 3c50046..9df2d09 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3108,6 +3108,9 @@ static int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
bool migrated = false;
int flags = 0;
+ /* A PROT_NONE fault should not end up here */
+ BUG_ON(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)));
+
/*
* The "pte" at this point cannot be used safely without
* validation through pte_unmap_same(). It's of NUMA type but
--
2.1.2
next prev parent reply other threads:[~2015-01-05 10:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-05 10:54 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v5 Mel Gorman
2015-01-05 10:54 ` [PATCH 01/10] mm: numa: Do not dereference pmd outside of the lock during NUMA hinting fault Mel Gorman
2015-01-05 10:54 ` [PATCH 02/10] mm: Add p[te|md] protnone helpers for use by NUMA balancing Mel Gorman
2015-01-05 10:54 ` [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone_numa Mel Gorman
2015-01-05 10:54 ` [PATCH 04/10] ppc64: Add paranoid warnings for unexpected DSISR_PROTFAULT Mel Gorman
2015-01-05 10:54 ` [PATCH 05/10] mm: Convert p[te|md]_mknonnuma and remaining page table manipulations Mel Gorman
2015-01-05 10:54 ` [PATCH 06/10] mm: Remove remaining references to NUMA hinting bits and helpers Mel Gorman
2015-01-05 10:54 ` [PATCH 07/10] mm: numa: Do not trap faults on the huge zero page Mel Gorman
2015-01-05 10:54 ` [PATCH 08/10] x86: mm: Restore original pte_special check Mel Gorman
2015-01-05 10:54 ` Mel Gorman [this message]
2015-01-05 10:54 ` [PATCH 10/10] mm: numa: Avoid unnecessary TLB flushes when setting NUMA hinting entries Mel Gorman
-- strict thread matches above, loose matches on Subject: below --
2014-12-04 11:24 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v4 Mel Gorman
2014-12-04 11:24 ` [PATCH 09/10] mm: numa: Add paranoid check around pte_protnone_numa Mel Gorman
2014-11-21 13:57 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v3 Mel Gorman
2014-11-21 13:57 ` [PATCH 09/10] mm: numa: Add paranoid check around pte_protnone_numa Mel Gorman
2014-11-20 10:19 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v2 Mel Gorman
2014-11-20 10:19 ` [PATCH 09/10] mm: numa: Add paranoid check around pte_protnone_numa Mel Gorman
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