The patch titled
Subject: mm: numa: add paranoid check around pte_protnone_numa
has been added to the -mm tree. Its filename is
mm-numa-add-paranoid-check-around-pte_protnone_numa.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-numa-add-paranoid-check-around-pte_protnone_numa.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-numa-add-paranoid-check-around-pte_protnone_numa.patch
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------------------------------------------------------
From: Mel Gorman <mgorman@xxxxxxx>
Subject: mm: numa: add paranoid check around pte_protnone_numa
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@xxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Dave Jones <davej@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Kirill Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Sasha Levin <sasha.levin@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 3 +++
mm/memory.c | 3 +++
2 files changed, 6 insertions(+)
diff -puN mm/huge_memory.c~mm-numa-add-paranoid-check-around-pte_protnone_numa mm/huge_memory.c
--- a/mm/huge_memory.c~mm-numa-add-paranoid-check-around-pte_protnone_numa
+++ a/mm/huge_memory.c
@@ -1268,6 +1268,9 @@ int do_huge_pmd_numa_page(struct mm_stru
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 -puN mm/memory.c~mm-numa-add-paranoid-check-around-pte_protnone_numa mm/memory.c
--- a/mm/memory.c~mm-numa-add-paranoid-check-around-pte_protnone_numa
+++ a/mm/memory.c
@@ -3010,6 +3010,9 @@ static int do_numa_page(struct mm_struct
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
_
Patches currently in -mm which might be from mgorman@xxxxxxx are
mm-debug-pagealloc-prepare-boottime-configurable-on-off.patch
mm-vmscan-prevent-kswapd-livelock-due-to-pfmemalloc-throttled-process-being-killed.patch
mm-page_alloc-place-zone_id-check-before-vm_bug_on_page-check.patch
mm-vmscan-wake-up-all-pfmemalloc-throttled-processes-at-once.patch
mm-numa-do-not-dereference-pmd-outside-of-the-lock-during-numa-hinting-fault.patch
mm-add-p-protnone-helpers-for-use-by-numa-balancing.patch
mm-convert-p_numa-users-to-p_protnone_numa.patch
ppc64-add-paranoid-warnings-for-unexpected-dsisr_protfault.patch
mm-convert-p_mknonnuma-and-remaining-page-table-manipulations.patch
mm-remove-remaining-references-to-numa-hinting-bits-and-helpers.patch
mm-numa-do-not-trap-faults-on-the-huge-zero-page.patch
x86-mm-restore-original-pte_special-check.patch
mm-numa-add-paranoid-check-around-pte_protnone_numa.patch
mm-numa-avoid-unnecessary-tlb-flushes-when-setting-numa-hinting-entries.patch
do_shared_fault-check-that-mmap_sem-is-held.patch
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