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authorChen, Kenneth W <kenneth.w.chen@intel.com>2006-10-11 01:20:46 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-11 11:14:15 -0700
commit502717f4e112b18d9c37753a32f675bec9f2838b (patch)
tree90e674229bbd7caa05e740dfe719cf8749d0eb27 /mm/hugetlb.c
parent97c7801cd5b0bb6a38c16108a496235474dc6310 (diff)
[PATCH] hugetlb: fix linked list corruption in unmap_hugepage_range()
commit fe1668ae5bf0145014c71797febd9ad5670d5d05 causes kernel to oops with libhugetlbfs test suite. The problem is that hugetlb pages can be shared by multiple mappings. Multiple threads can fight over page->lru in the unmap path and bad things happen. We now serialize __unmap_hugepage_range to void concurrent linked list manipulation. Such serialization is also needed for shared page table page on hugetlb area. This patch will fixed the bug and also serve as a prepatch for shared page table. Signed-off-by: Ken Chen <kenneth.w.chen@intel.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c22
1 files changed, 20 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 1d709ff528e..2dbec90dc3b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -356,8 +356,8 @@ nomem:
return -ENOMEM;
}
-void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
- unsigned long end)
+void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
@@ -398,6 +398,24 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
}
}
+void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end)
+{
+ /*
+ * It is undesirable to test vma->vm_file as it should be non-null
+ * for valid hugetlb area. However, vm_file will be NULL in the error
+ * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails,
+ * do_mmap_pgoff() nullifies vma->vm_file before calling this function
+ * to clean up. Since no pte has actually been setup, it is safe to
+ * do nothing in this case.
+ */
+ if (vma->vm_file) {
+ spin_lock(&vma->vm_file->f_mapping->i_mmap_lock);
+ __unmap_hugepage_range(vma, start, end);
+ spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock);
+ }
+}
+
static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *ptep, pte_t pte)
{