Hi Greg, hi Sasha, Please consider to include following fixes in to stable tree. The 6 patches from Ming was fixing a deadlock, they are included around kernel 5.3/4. Would be good to included in 4.19, we hit it during testing, with the fix we no longer hit the deadlock. The last one is simple NULL pointer deref fix. Thanks! Jack Wang @ IONOS Cloud. v1: https://lore.kernel.org/stable/20210203132022.92406-1-jinpu.wang@xxxxxxxxxxxxxxx/ Ming Lei (6): block: don't hold q->sysfs_lock in elevator_init_mq blk-mq: don't hold q->sysfs_lock in blk_mq_map_swqueue block: add helper for checking if queue is registered block: split .sysfs_lock into two locks block: fix race between switching elevator and removing queues block: don't release queue's sysfs lock during switching elevator zhengbin (1): block: fix NULL pointer dereference in register_disk block/blk-core.c | 1 + block/blk-mq-sysfs.c | 12 +++++------ block/blk-mq.c | 7 ------ block/blk-sysfs.c | 49 +++++++++++++++++++++++++++--------------- block/blk-wbt.c | 2 +- block/blk.h | 2 +- block/elevator.c | 44 +++++++++++++++++++++---------------- block/genhd.c | 10 +++++---- include/linux/blkdev.h | 2 ++ 9 files changed, 74 insertions(+), 55 deletions(-) -- 2.25.1
