diff options
| author | Luck, Tony <tony.luck@intel.com> | 2010-08-24 11:44:18 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-10-28 21:04:14 -0700 |
| commit | 207988da56b71bb6882f19c925b40e8349374e2e (patch) | |
| tree | 56d4265fdaf794dde95f420bc608a5a11a23c9bf | |
| parent | 5f2a867eb3cb6558cf82c96b56d52260a276111d (diff) | |
guard page for stacks that grow upwards
commit 8ca3eb08097f6839b2206e2242db4179aee3cfb3 upstream.
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>
Cc: dann frazier <dannf@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | include/linux/mm.h | 8 | ||||
| -rw-r--r-- | mm/memory.c | 15 | ||||
| -rw-r--r-- | mm/mmap.c | 3 |
3 files changed, 18 insertions, 8 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index eeb7e56b15a..c20007caa48 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -87,7 +87,11 @@ extern unsigned int kobjsize(const void *objp); #define VM_MAYSHARE 0x00000080 #define VM_GROWSDOWN 0x00000100 /* general info on the segment */ +#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) #define VM_GROWSUP 0x00000200 +#else +#define VM_GROWSUP 0x00000000 +#endif #define VM_PFNMAP 0x00000400 /* Page-ranges managed without "struct page", just pure PFN */ #define VM_DENYWRITE 0x00000800 /* ETXTBSY on write attempts.. */ @@ -1181,8 +1185,10 @@ unsigned long max_sane_readahead(unsigned long nr); /* Do stack extension */ extern int expand_stack(struct vm_area_struct *vma, unsigned long address); -#ifdef CONFIG_IA64 +#if VM_GROWSUP extern int expand_upwards(struct vm_area_struct *vma, unsigned long address); +#else + #define expand_upwards(vma, address) do { } while (0) #endif extern int expand_stack_downwards(struct vm_area_struct *vma, unsigned long address); diff --git a/mm/memory.c b/mm/memory.c index f0282eb8650..57309b164a5 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2396,11 +2396,9 @@ out_nomap: } /* - * 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) { @@ -2412,6 +2410,15 @@ static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned lo expand_stack(vma, address); } + 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 08a32cfabd5..17d640d33df 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1589,9 +1589,6 @@ static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, un * 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 inline -#endif int expand_upwards(struct vm_area_struct *vma, unsigned long address) { int error; |