Hi Andrew, My patch 8d63d99a5dfb which was merged during 4.1 merge window caused regression: page:ffffea0010a15040 count:0 mapcount:1 mapping: (null) index:0x0 flags: 0x8000000000008014(referenced|dirty|tail) page dumped because: VM_BUG_ON_PAGE(page_mapcount(page) != 0) ------------[ cut here ]------------ kernel BUG at mm/swap.c:134! The patch was reverted by Linus. This VM_BUG_ON_PAGE() is bogus. The first patch explains why the assert is wrong and removes it. The second re-introduces original patch. Kirill A. Shutemov (2): mm: drop bogus VM_BUG_ON_PAGE assert in put_page() codepath mm: avoid tail page refcounting on non-THP compound pages include/linux/mm.h | 2 +- mm/swap.c | 1 - 2 files changed, 1 insertion(+), 2 deletions(-) -- 2.1.4 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>