Hello, KVM is hanging on postcopy live migration.
David tracked it down to commit ce53053ce378c21e7ffc45241fd67d6ee79daa2b and the problem is pretty obvious then. Either we teach get_user_pages_locked/unlocked to handle FOLL_NOWAIT (so faultin_nopage works right even when the nonblocking pointer is not NULL) or we need to revert part of commit ce53053ce378c21e7ffc45241fd67d6ee79daa2b and keep using FOLL_NOWAIT only as parameter to get_user_pages (which won't ever set nonblocking pointer to non-NULL). I suppose the former approach is preferred to be more robust. Thanks, Andrea Andrea Arcangeli (1): mm: gup: teach get_user_pages_unlocked to handle FOLL_NOWAIT mm/gup.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
