Hi mm folks: I reported a regression bug on latest upstream linux: https://bugzilla.kernel.org/show_bug.cgi?id=216047 It's about xfs/ext4 + DAX, panic at mm/page_table_check.c:51! static struct page_table_check *get_page_table_check(struct page_ext *page_ext) { ==> BUG_ON(!page_ext); return (void *)(page_ext) + page_table_check_ops.offset; } It's 100% reproducible for me, by running fstests generic/623: https://git.kernel.org/pub/scm/fs/xfs/xfstests-dev.git/tree/tests/generic/623 on xfs or ext4 with DAX enabled. It doesn't look like a xfs or ext4 issue, so send to linux-mm to get more reviewing. More details please refer to above bug link. I changed its Pruduct to mm, but the Assignee isn't changed by default. Thanks, Zorro