tree 832a652ea61f198004cd27bfa8cc56a24087d422
parent 982785c6b05a82c01e90687b7e25ee87c8970b2e
author Kirill A. Shutemov <kirill.shutemov@linux.intel.com> 1474321447 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1474324576 -0700

mm: avoid endless recursion in dump_page()

dump_page() uses page_mapcount() to get mapcount of the page.
page_mapcount() has VM_BUG_ON_PAGE(PageSlab(page)) as mapcount doesn't
make sense for slab pages and the field in struct page used for other
information.

It leads to recursion if dump_page() called for slub page and DEBUG_VM
is enabled:

dump_page() -> page_mapcount() -> VM_BUG_ON_PAGE() -> dump_page -> ...

Let's avoid calling page_mapcount() for slab pages in dump_page().

Link: http://lkml.kernel.org/r/20160908082137.131076-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>