diff options
| author | Mel Gorman <[email protected]> | 2015-02-12 14:58:41 -0800 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2015-02-12 18:54:08 -0800 |
| commit | c0e7cad9f2390087b53e26e7b98958d8793ee02d (patch) | |
| tree | 76b69e566d2106fc4a28c17654928cdfafc2c7e4 | |
| parent | c819f37e7e174d68cd013abf33725b4e07ced023 (diff) | |
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 <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Dave Jones <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Kirill Shutemov <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Sasha Levin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
| -rw-r--r-- | mm/huge_memory.c | 3 | ||||
| -rw-r--r-- | mm/memory.c | 3 |
2 files changed, 6 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 8e791a3db6b6..8e07342b52c0 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1262,6 +1262,9 @@ 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 bf244f56b05a..f7886ab036e7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3013,6 +3013,9 @@ 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 |