Messages in this thread | | | From | Akinobu Mita <> | Subject | [PATCH v3 0/7] blk-mq: fix race conditions on cpu hotplug handling | Date | Sun, 19 Jul 2015 01:28:16 +0900 |
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This patchset addresses several race conditions on cpu hotplug handling for blk-mq. All problems can be reproducible by the following script.
while true; do echo 0 > /sys/devices/system/cpu/cpu1/online echo 1 > /sys/devices/system/cpu/cpu1/online done &
while true; do modprobe -r null_blk modprobe null_blk queue_mode=2 irqmode=1 sleep 0.1 done
* Changes from v2 - Add regression fix for hctx->tags->cpumask - Remove BLK_MQ_F_SYSFS_UP per-hctx flag and use mq_sysfs_init_done per-queue flag instead with appropriate locking in order to keep track of 'mq' sysfs entry's life - Add comments on non-trivial stuffs, suggested by Ming
* Changes from v1 - Release q->mq_map in blk_mq_release() - Fix deadlock when reading cpu_list - Fix race freeze and unfreeze
Akinobu Mita (7): blk-mq: avoid access hctx->tags->cpumask before allocation blk-mq: fix sysfs registration/unregistration race blk-mq: Fix use after of free q->mq_map blk-mq: fix q->mq_usage_counter access race blk-mq: avoid inserting requests before establishing new mapping blk-mq: fix freeze queue race blk-mq: fix deadlock when reading cpu_list
block/blk-core.c | 1 + block/blk-mq-cpumap.c | 9 +++-- block/blk-mq-sysfs.c | 36 ++++++++++++------ block/blk-mq.c | 100 +++++++++++++++++++++++++++++++++++++------------ block/blk-mq.h | 3 +- include/linux/blk-mq.h | 1 - include/linux/blkdev.h | 8 ++++ 7 files changed, 116 insertions(+), 42 deletions(-)
Cc: Jens Axboe <axboe@kernel.dk> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Keith Busch <keith.busch@intel.com> -- 1.9.1
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