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authorLuck, Tony <tony.luck@intel.com>2010-08-24 11:44:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-24 12:13:20 -0700
commit8ca3eb08097f6839b2206e2242db4179aee3cfb3 (patch)
tree32b9f033230d615d248fa0bbfa1a0c644a422ed8 /mm
parent9559fcdbff4f93d29af04478bbc48294519424f5 (diff)
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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')
-rw-r--r--mm/memory.c15
-rw-r--r--mm/mmap.c3
2 files changed, 11 insertions, 7 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 2ed2267439d..6b2ab105185 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2760,11 +2760,9 @@ out_release:
}
/*
- * This is like a special single-page "expand_downwards()",
- * except we must first make sure that 'address-PAGE_SIZE'
+ * This is like a special single-page "expand_{down|up}wards()",
+ * except we must first make sure that 'address{-|+}PAGE_SIZE'
* doesn't hit another vma.
- *
- * The "find_vma()" will do the right thing even if we wrap
*/
static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
{
@@ -2783,6 +2781,15 @@ static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned lo
expand_stack(vma, address - PAGE_SIZE);
}
+ if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
+ struct vm_area_struct *next = vma->vm_next;
+
+ /* As VM_GROWSDOWN but s/below/above/ */
+ if (next && next->vm_start == address + PAGE_SIZE)
+ return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
+
+ expand_upwards(vma, address + PAGE_SIZE);
+ }
return 0;
}
diff --git a/mm/mmap.c b/mm/mmap.c
index 331e51af38c..6128dc8e5ed 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1716,9 +1716,6 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns
* PA-RISC uses this for its stack; IA64 for its Register Backing Store.
* vma is the last one with address > vma->vm_end. Have to extend vma.
*/
-#ifndef CONFIG_IA64
-static
-#endif
int expand_upwards(struct vm_area_struct *vma, unsigned long address)
{
int error;