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authorAdam Litke <agl@us.ibm.com>2007-01-30 14:35:39 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-01-30 16:01:35 -0800
commit0d59a01bc461bbab4017ff449b8401151ef44cf6 (patch)
treeec388c127883f8dddde3a933eac44a45aca6520c
parentbcdddfb66cc998252d34758ce4109cedc0d24a5c (diff)
downloadlinux-2.6.34-ux500-0d59a01bc461bbab4017ff449b8401151ef44cf6.tar.gz
[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 <agl@us.ibm.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/mmap.c7
1 files changed, 7 insertions, 0 deletions
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.