From: Yu Kuai <yukuai3@xxxxxxxxxx> Our syzkaller report a UAF problem(details in patch 1), however it can't be reporduced. And this set are some corner cases fix that might be related, and they are found by code review. Yu Kuai (4): block, bfq: fix possible UAF for bfqq->bic with merge chain block, bfq: choose the last bfqq from merge chain in bfq_setup_cooperator() block, bfq: don't break merge chain in bfq_split_bfqq() block, bfq: use bfq_reassign_last_bfqq() in bfq_bfqq_move() block/bfq-cgroup.c | 7 +------ block/bfq-iosched.c | 17 +++++++++++------ block/bfq-iosched.h | 2 ++ 3 files changed, 14 insertions(+), 12 deletions(-) -- 2.39.2