diff options
| author | Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> | 2011-05-09 13:01:09 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-05-21 15:13:07 -0700 |
| commit | e277c750ea81076d8dc68694acc7994a024d83b2 (patch) | |
| tree | 5bb1a87f3c6f05d348a823be4d1685431bf09bcb /mm/memory.c | |
| parent | 3dead919f4cf95df59d8df06c1fa559c55571384 (diff) | |
Don't lock guardpage if the stack is growing up
commit a09a79f66874c905af35d5bb5e5f2fdc7b6b894d upstream.
Linux kernel excludes guard page when performing mlock on a VMA with
down-growing stack. However, some architectures have up-growing stack
and locking the guard page should be excluded in this case too.
This patch fixes lvm2 on PA-RISC (and possibly other architectures with
up-growing stack). lvm2 calculates number of used pages when locking and
when unlocking and reports an internal error if the numbers mismatch.
[ Patch changed fairly extensively to also fix /proc/<pid>/maps for the
grows-up case, and to move things around a bit to clean it all up and
share the infrstructure with the /proc bits.
Tested on ia64 that has both grow-up and grow-down segments - Linus ]
Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Tested-by: Tony Luck <tony.luck@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 16 |
1 files changed, 7 insertions, 9 deletions
diff --git a/mm/memory.c b/mm/memory.c index 8b2bb7dcdae..c8fff702774 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1412,9 +1412,8 @@ no_page_table: static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr) { - return (vma->vm_flags & VM_GROWSDOWN) && - (vma->vm_start == addr) && - !vma_stack_continue(vma->vm_prev, addr); + return stack_guard_page_start(vma, addr) || + stack_guard_page_end(vma, addr+PAGE_SIZE); } int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, @@ -1502,12 +1501,6 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, continue; } - /* - * For mlock, just skip the stack guard page. - */ - if ((gup_flags & FOLL_MLOCK) && stack_guard_page(vma, start)) - goto next_page; - do { struct page *page; unsigned int foll_flags = gup_flags; @@ -1524,6 +1517,11 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, int ret; unsigned int fault_flags = 0; + /* For mlock, just skip the stack guard page. */ + if (foll_flags & FOLL_MLOCK) { + if (stack_guard_page(vma, start)) + goto next_page; + } if (foll_flags & FOLL_WRITE) fault_flags |= FAULT_FLAG_WRITE; if (nonblocking) |