thp: avoid dumping huge zero page
No reason to preserve the huge zero page in core dumps.
Reported-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 6001ee6..b5783d8 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1257,6 +1257,10 @@
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) {