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| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2012-12-12 13:50:57 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-12 17:38:31 -0800 |
| commit | cad7f613c4d010e1d0f05c9a4fb33c7ae40ba115 (patch) | |
| tree | 9d3f13bfbec1215e2427bb1ef74d8471d4e0b995 | |
| parent | 93b4796dede916de74b21fbd637588da6a99a7ec (diff) | |
| download | linux-cad7f613c4d010e1d0f05c9a4fb33c7ae40ba115.tar.gz linux-cad7f613c4d010e1d0f05c9a4fb33c7ae40ba115.tar.bz2 linux-cad7f613c4d010e1d0f05c9a4fb33c7ae40ba115.zip | |
thp: change_huge_pmd(): make sure we don't try to make a page writable
mprotect core never tries to make page writable using change_huge_pmd().
Let's add an assert that the assumption is true. It's important to be
sure we will not make huge zero page writable.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/huge_memory.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index a959b3a4ddd5..7742fb36eb4d 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1273,6 +1273,7 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, pmd_t entry; entry = pmdp_get_and_clear(mm, addr, pmd); entry = pmd_modify(entry, newprot); + BUG_ON(pmd_write(entry)); set_pmd_at(mm, addr, pmd, entry); spin_unlock(&vma->vm_mm->page_table_lock); ret = 1; |