From 0d59a01bc461bbab4017ff449b8401151ef44cf6 Mon Sep 17 00:00:00 2001 From: Adam Litke Date: Tue, 30 Jan 2007 14:35:39 -0800 Subject: [PATCH] Don't allow the stack to grow into hugetlb reserved regions When expanding the stack, we don't currently check if the VMA will cross into an area of the address space that is reserved for hugetlb pages. Subsequent faults on the expanded portion of such a VMA will confuse the low-level MMU code, resulting in an OOPS. Check for this. Signed-off-by: Adam Litke Cc: David Gibson Cc: William Lee Irwin III Cc: Hugh Dickins Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/mmap.c b/mm/mmap.c index 9717337293c..cc3a2081945 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1477,6 +1477,7 @@ static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, un { struct mm_struct *mm = vma->vm_mm; struct rlimit *rlim = current->signal->rlim; + unsigned long new_start; /* address space limit tests */ if (!may_expand_vm(mm, grow)) @@ -1496,6 +1497,12 @@ static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, un return -ENOMEM; } + /* Check to ensure the stack will not grow into a hugetlb-only region */ + new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : + vma->vm_end - size; + if (is_hugepage_only_range(vma->vm_mm, new_start, size)) + return -EFAULT; + /* * Overcommit.. This must be the final test, as it will * update security statistics. -- cgit v1.2.3