thp: avoid dumping huge zero page

No reason to preserve the huge zero page in core dumps. Reported-by: Michel Lespinasse <[email protected]> Signed-off-by: Kirill A. Shutemov <[email protected]> Reviewed-by: Michel Lespinasse <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
chewitt · Feb 5, 2013 · 85facf2 · 85facf2
1 parent a9bae18
commit 85facf2
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
@@ -1257,6 +1257,10 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
 	if (flags & FOLL_WRITE && !pmd_write(*pmd))
 		goto out;
 
+	/* Avoid dumping huge zero page */
+	if ((flags & FOLL_DUMP) && is_huge_zero_pmd(*pmd))
+		return ERR_PTR(-EFAULT);
+
 	page = pmd_page(*pmd);
 	VM_BUG_ON(!PageHead(page));
 	if (flags & FOLL_TOUCH) {