Revert "mm: do not collapse stack gap into THP"

This reverts commit e9dbbeb2e0b61881d67ba7818fd4b3f996a35f0b to be
replaced by the upstream patch set.

CVE-2017-1000364

Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 75719aa0443a322f8008f64459d52256df77a34e..49cb70b5993deddd13e54fda231f14cf414ce543 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -660,9 +660,6 @@ int do_huge_pmd_anonymous_page(struct vm_fault *vmf)
 
        if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
                return VM_FAULT_FALLBACK;
-       if (stack_guard_area(vma, haddr) ||
-                       stack_guard_area(vma, haddr + HPAGE_PMD_SIZE))
-               return VM_FAULT_FALLBACK;
        if (unlikely(anon_vma_prepare(vma)))
                return VM_FAULT_OOM;
        if (unlikely(khugepaged_enter(vma, vma->vm_flags)))

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 16379e5943a6c2d09b825e5b9d5e67c7c69ffcda..77ae3239c3de17bfbf7ba29b56a5cb270611cfd8 100644 (file)
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -859,10 +859,6 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
                return SCAN_ADDRESS_RANGE;
        if (!hugepage_vma_check(vma))
                return SCAN_VMA_CHECK;
-
-       /* never try to collapse stack gap */
-       if (stack_guard_area(vma, hstart) || stack_guard_area(vma, hend))
-               return SCAN_ADDRESS_RANGE;
        return 0;
 }