Ming Lei 506a2001b7 block: fix race between adding/removing rq qos and normal IO ... [ Upstream commit 2cafe29a8d ] Yi reported several kernel panics on: [16687.001777] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 ... [16687.163549] pc : __rq_qos_track+0x38/0x60 or [ 997.690455] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 ... [ 997.850347] pc : __rq_qos_done+0x2c/0x50 Turns out it is caused by race between adding rq qos(wbt) and normal IO because rq_qos_add can be run when IO is being submitted, fix this issue by freezing queue before adding/deleting rq qos to queue. rq_qos_exit() needn't to freeze queue because it is called after queue has been frozen. iolatency calls rq_qos_add() during allocating queue, so freezing won't add delay because queue usage refcount works at atomic mode at that time. iocost calls rq_qos_add() when writing cgroup attribute file, that is fine to freeze queue at that time since we usually freeze queue when storing to queue sysfs attribute, meantime iocost only exists on the root cgroup. wbt_init calls it in blk_register_queue() and queue sysfs attribute store(queue_wb_lat_store() when write it 1st time in case of !BLK_WBT_MQ), the following patch will speedup the queue freezing in wbt_init. Reported-by: Yi Zhang <yi.zhang@redhat.com> Cc: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Yi Zhang <yi.zhang@redhat.com> Link: https://lore.kernel.org/r/20210609015822.103433-2-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>		2021-07-14 16:53:18 +02:00
..
partitions
badblocks.c
bfq-cgroup.c
bfq-iosched.c	kyber: fix out of bounds access when preempted	2021-05-19 10:08:30 +02:00
bfq-iosched.h
bfq-wf2q.c
bio-integrity.c
bio.c	block: only update parent bi_status when bio fail	2021-04-16 11:46:38 +02:00
blk-cgroup.c	blk-cgroup: Use cond_resched() when destroy blkgs	2021-02-13 13:52:56 +01:00
blk-core.c	Revert "Revert "block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT""	2021-02-07 15:35:47 +01:00
blk-exec.c
blk-flush.c
blk-integrity.c
blk-ioc.c
blk-iocost.c
blk-iolatency.c
blk-lib.c
blk-map.c
blk-merge.c	block: recalculate segment count for multi-segment discards correctly	2021-03-30 14:35:28 +02:00
blk-mq-cpumap.c
blk-mq-debugfs-zoned.c
blk-mq-debugfs.c
blk-mq-debugfs.h
blk-mq-pci.c
blk-mq-rdma.c
blk-mq-sched.c	kyber: fix out of bounds access when preempted	2021-05-19 10:08:30 +02:00
blk-mq-sched.h
blk-mq-sysfs.c	blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue	2020-10-29 09:57:34 +01:00
blk-mq-tag.c
blk-mq-tag.h
blk-mq-virtio.c
blk-mq.c	blk-mq: Swap two calls in blk_mq_exit_queue()	2021-05-19 10:08:30 +02:00
blk-mq.h
blk-pm.c	scsi: block: Fix a race in the runtime power management code	2021-01-06 14:48:37 +01:00
blk-pm.h
blk-rq-qos.c
blk-rq-qos.h	block: fix race between adding/removing rq qos and normal IO	2021-07-14 16:53:18 +02:00
blk-settings.c	blk-settings: align max_sectors on "logical_block_size" boundary	2021-03-04 10:26:40 +01:00
blk-softirq.c
blk-stat.c
blk-stat.h
blk-sysfs.c	blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue	2020-10-29 09:57:34 +01:00
blk-throttle.c
blk-timeout.c
blk-wbt.c
blk-wbt.h
blk-zoned.c	block: Simplify REQ_OP_ZONE_RESET_ALL handling	2020-12-30 11:50:54 +01:00
blk.h
bounce.c
bsg-lib.c
bsg.c	bsg: free the request before return error code	2021-03-04 10:26:22 +01:00
cmdline-parser.c
compat_ioctl.c
elevator.c
genhd.c	block: Suppress uevent for hidden device when removed	2021-03-30 14:35:23 +02:00
ioctl.c
ioprio.c
Kconfig
Kconfig.iosched
kyber-iosched.c	kyber: fix out of bounds access when preempted	2021-05-19 10:08:30 +02:00
Makefile
mq-deadline.c	kyber: fix out of bounds access when preempted	2021-05-19 10:08:30 +02:00
opal_proto.h
partition-generic.c
scsi_ioctl.c
sed-opal.c
t10-pi.c