Hi,
Since 45a9c9d909b2 ("blk-mq: Fix a use-after-free"), run queue isn't
allowed during cleanup queue even though queue refcount is held.
This change has caused lots of kernel oops triggered in run queue path,
turns out it isn't easy to fix them all.
So move freeing of hw queue resources into hctx's release handler, then
the above issue is fixed. Meantime, this way is safe given freeing hw
queue resource doesn't require tags.
V3 covers more races.
V9:
- fix one issue in patch 1 of V8 by put the queue usage counter in
early return branch
- make patch 4 of V8 a bit clean, as suggested by Christoph and
Hannes
V8:
- merge the 4th and 5th of V7 into one patch, as suggested by Christoph
- drop the 9th patch
V7:
- add reviewed-by and tested-by tag
- rename "dead_hctx" as "unused_hctx"
- check if there are live hctx in queue's release handler
- only patch 6 is modified
V6:
- remove previous SCSI patch which will be routed via SCSI tree
- add reviewed-by tag
- fix one related NVMe scan vs reset race
V5:
- refactor blk_mq_alloc_and_init_hctx()
- fix race related updating nr_hw_queues by always freeing hctx
after request queue is released
V4:
- add patch for fixing potential use-after-free in
blk_mq_update_nr_hw_queues
- fix comment in the last patch
V3:
- cancel q->requeue_work in queue's release handler
- cancel hctx->run_work in hctx's release handler
- add patch 1 for fixing race in plug code path
- the last patch is added for avoiding to grab SCSI's refcont
in IO path
V2:
- moving freeing hw queue resources into hctx's release handler
Ming Lei (7):
blk-mq: grab .q_usage_counter when queuing request from plug code path
blk-mq: move cancel of requeue_work into blk_mq_release
blk-mq: free hw queue's resource in hctx's release handler
blk-mq: split blk_mq_alloc_and_init_hctx into two parts
blk-mq: always free hctx after request queue is freed
blk-mq: move cancel of hctx->run_work into blk_mq_hw_sysfs_release
block: don't drain in-progress dispatch in blk_cleanup_queue()
block/blk-core.c | 23 +-----
block/blk-mq-sched.c | 12 +++-
block/blk-mq-sysfs.c | 8 +++
block/blk-mq.c | 189 ++++++++++++++++++++++++++++---------------------
block/blk-mq.h | 2 +-
include/linux/blk-mq.h | 2 +
include/linux/blkdev.h | 7 ++
7 files changed, 139 insertions(+), 104 deletions(-)
Cc: Dongli Zhang <dongli.zh...@oracle.com>
Cc: James Smart <james.sm...@broadcom.com>
Cc: Bart Van Assche <bart.vanass...@wdc.com>
Cc: linux-scsi@vger.kernel.org,
Cc: Martin K . Petersen <martin.peter...@oracle.com>,
Cc: Christoph Hellwig <h...@lst.de>,
Cc: James E . J . Bottomley <j...@linux.vnet.ibm.com>,
--
2.9.5
