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authorLuck, Tony <tony.luck@intel.com>2010-08-24 14:44:18 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-24 15:13:20 -0400
commit8ca3eb08097f6839b2206e2242db4179aee3cfb3 (patch)
tree32b9f033230d615d248fa0bbfa1a0c644a422ed8 /mm/memory.c
parent9559fcdbff4f93d29af04478bbc48294519424f5 (diff)
guard page for stacks that grow upwards
pa-risc and ia64 have stacks that grow upwards. Check that they do not run into other mappings. By making VM_GROWSUP 0x0 on architectures that do not ever use it, we can avoid some unpleasant #ifdefs in check_stack_guard_page(). Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 2ed2267439df..6b2ab1051851 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2760,11 +2760,9 @@ out_release:
2760} 2760}
2761 2761
2762/* 2762/*
2763 * This is like a special single-page "expand_downwards()", 2763 * This is like a special single-page "expand_{down|up}wards()",
2764 * except we must first make sure that 'address-PAGE_SIZE' 2764 * except we must first make sure that 'address{-|+}PAGE_SIZE'
2765 * doesn't hit another vma. 2765 * doesn't hit another vma.
2766 *
2767 * The "find_vma()" will do the right thing even if we wrap
2768 */ 2766 */
2769static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address) 2767static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
2770{ 2768{
@@ -2783,6 +2781,15 @@ static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned lo
2783 2781
2784 expand_stack(vma, address - PAGE_SIZE); 2782 expand_stack(vma, address - PAGE_SIZE);
2785 } 2783 }
2784 if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
2785 struct vm_area_struct *next = vma->vm_next;
2786
2787 /* As VM_GROWSDOWN but s/below/above/ */
2788 if (next && next->vm_start == address + PAGE_SIZE)
2789 return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
2790
2791 expand_upwards(vma, address + PAGE_SIZE);
2792 }
2786 return 0; 2793 return 0;
2787} 2794}
2788 2795