diff options
| author | Luck, Tony <tony.luck@intel.com> | 2010-08-24 11:44:18 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-24 12:13:20 -0700 |
| commit | 8ca3eb08097f6839b2206e2242db4179aee3cfb3 (patch) | |
| tree | 32b9f033230d615d248fa0bbfa1a0c644a422ed8 /mm/memory.c | |
| parent | 9559fcdbff4f93d29af04478bbc48294519424f5 (diff) | |
| download | lwn-8ca3eb08097f6839b2206e2242db4179aee3cfb3.tar.gz lwn-8ca3eb08097f6839b2206e2242db4179aee3cfb3.zip | |
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.c | 15 |
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: } /* - * 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; } |