linux/block
Dennis Zhou 0273ac349f blkcg: handle dying request_queue when associating a blkg
Between v3 [1] and v4 [2] of the blkg association series, the
association point moved from generic_make_request_checks(), which is
called after the request enters the queue, to bio_set_dev(), which is when
the bio is formed before submit_bio(). When the request_queue goes away,
the blkgs supporting the request_queue are destroyed and then the
q->root_blkg is set to %NULL.

This patch adds a %NULL check to blkg_tryget_closest() to prevent the
NPE caused by the above. It also adds a guard to see if the
request_queue is dying when creating a blkg to prevent creating a blkg
for a dead request_queue.

[1] https://lore.kernel.org/lkml/20180911184137.35897-1-dennisszhou@gmail.com/
[2] https://lore.kernel.org/lkml/20181126211946.77067-1-dennis@kernel.org/

Fixes: 5cdf2e3fea ("blkcg: associate blkg when associating a device")
Reported-and-tested-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-12 17:43:33 -07:00
..
partitions partitions/aix: append null character to print data from disk 2018-07-27 09:17:41 -06:00
badblocks.c badblocks: fix wrong return value in badblocks_set if badblocks are disabled 2017-11-03 11:29:50 -07:00
bfq-cgroup.c blkcg: fix ref count issue with bio_blkcg() using task_css 2018-12-07 22:26:36 -07:00
bfq-iosched.c Linux 4.20-rc6 2018-12-09 17:45:40 -07:00
bfq-iosched.h block, bfq: fix decrement of num_active_groups 2018-12-07 07:40:07 -07:00
bfq-wf2q.c block, bfq: fix decrement of num_active_groups 2018-12-07 07:40:07 -07:00
bio-integrity.c block: remove bio_rewind_iter() 2018-09-06 15:12:24 -06:00
bio.c block: delete part_round_stats and switch to less precise counting 2018-12-10 08:30:37 -07:00
blk-cgroup.c blkcg: handle dying request_queue when associating a blkg 2018-12-12 17:43:33 -07:00
blk-core.c block: delete part_round_stats and switch to less precise counting 2018-12-10 08:30:37 -07:00
blk-exec.c block: remove dead elevator code 2018-11-07 13:42:32 -07:00
blk-flush.c block: add queue_is_mq() helper 2018-11-16 08:34:06 -07:00
blk-integrity.c block: merge BIOVEC_SEG_BOUNDARY into biovec_phys_mergeable 2018-09-24 12:33:57 -06:00
blk-ioc.c block: remove the queue_lock indirection 2018-11-15 12:17:28 -07:00
blk-iolatency.c block: convert io-latency to use rq_qos_wait 2018-12-07 22:26:38 -07:00
blk-lib.c block: fix 32 bit overflow in __blkdev_issue_discard() 2018-11-14 08:17:18 -07:00
blk-map.c Merge branch 'for-4.16/block' of git://git.kernel.dk/linux-block 2018-01-29 11:51:49 -08:00
blk-merge.c block: delete part_round_stats and switch to less precise counting 2018-12-10 08:30:37 -07:00
blk-mq-cpumap.c blk-mq: initial support for multiple queue maps 2018-11-07 13:45:00 -07:00
blk-mq-debugfs-zoned.c block: Make struct request_queue smaller for CONFIG_BLK_DEV_ZONED=n 2018-07-09 09:07:52 -06:00
blk-mq-debugfs.c block: remove QUEUE_FLAG_BYPASS and ->bypass 2018-11-15 12:13:15 -07:00
blk-mq-debugfs.h block: Make struct request_queue smaller for CONFIG_BLK_DEV_ZONED=n 2018-07-09 09:07:52 -06:00
blk-mq-pci.c blk-mq: initial support for multiple queue maps 2018-11-07 13:45:00 -07:00
blk-mq-rdma.c blk-mq: abstract out queue map 2018-11-07 13:44:59 -07:00
blk-mq-sched.c block: fix attempt to assign NULL io_context 2018-11-20 19:12:46 -07:00
blk-mq-sched.h block: Remove bio->bi_ioc 2018-11-19 19:03:44 -07:00
blk-mq-sysfs.c block: move queues types to the block layer 2018-12-04 11:38:17 -07:00
blk-mq-tag.c sbitmap: optimize wakeup check 2018-11-30 14:48:04 -07:00
blk-mq-tag.h Merge branch 'for-4.15/block' of git://git.kernel.dk/linux-block 2017-11-14 15:32:19 -08:00
blk-mq-virtio.c blk-mq: initial support for multiple queue maps 2018-11-07 13:45:00 -07:00
blk-mq.c block: return just one value from part_in_flight 2018-12-10 08:30:38 -07:00
blk-mq.h block: return just one value from part_in_flight 2018-12-10 08:30:38 -07:00
blk-pm.c block: remove the queue_lock indirection 2018-11-15 12:17:28 -07:00
blk-pm.h block: remove the queue_lock indirection 2018-11-15 12:17:28 -07:00
blk-rq-qos.c block: add rq_qos_wait to rq_qos 2018-12-07 22:26:38 -07:00
blk-rq-qos.h block: add rq_qos_wait to rq_qos 2018-12-07 22:26:38 -07:00
blk-settings.c block: use atomic bitops for ->queue_flags 2018-11-15 12:13:19 -07:00
blk-softirq.c block: remove a few unused exports 2018-11-15 12:13:25 -07:00
blk-stat.c block: remove a few unused exports 2018-11-15 12:13:25 -07:00
blk-stat.h block: deactivate blk_stat timer in wbt_disable_default() 2018-12-12 06:47:51 -07:00
blk-sysfs.c block: only allow polling if a poll queue_map exists 2018-12-04 11:38:19 -07:00
blk-throttle.c blkcg: consolidate bio_issue_init() to be a part of core 2018-12-07 22:26:37 -07:00
blk-timeout.c block: don't hold the queue_lock over blk_abort_request 2018-11-15 12:13:18 -07:00
blk-wbt.c block: deactivate blk_stat timer in wbt_disable_default() 2018-12-12 06:47:51 -07:00
blk-wbt.h block: remove external dependency on wbt_flags 2018-07-09 09:07:54 -06:00
blk-zoned.c block: add queue_is_mq() helper 2018-11-16 08:34:06 -07:00
blk.h block: sum requests in the plug structure 2018-11-26 10:35:22 -07:00
bounce.c blkcg: remove bio->bi_css and instead use bio->bi_blkg 2018-12-07 22:26:37 -07:00
bsg-lib.c bsg: move bsg-lib parts outside of request queue 2018-11-07 13:42:33 -07:00
bsg.c block: add queue_is_mq() helper 2018-11-16 08:34:06 -07:00
cmdline-parser.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compat_ioctl.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
elevator.c block: add queue_is_mq() helper 2018-11-16 08:34:06 -07:00
genhd.c block: return just one value from part_in_flight 2018-12-10 08:30:38 -07:00
ioctl.c block: Introduce BLKGETNRZONES ioctl 2018-10-25 11:17:40 -06:00
ioprio.c block: add ioprio_check_cap function 2018-05-31 10:50:54 -04:00
Kconfig blk-wbt: kill check for legacy queue type 2018-11-07 13:42:32 -07:00
Kconfig.iosched block: remove legacy IO schedulers 2018-11-07 13:42:32 -07:00
kyber-iosched.c blk-mq: allow software queue to map to multiple hardware queues 2018-11-07 13:44:59 -07:00
Makefile block: remove legacy IO schedulers 2018-11-07 13:42:32 -07:00
mq-deadline.c block: get rid of MQ scheduler ops union 2018-11-07 13:42:32 -07:00
opal_proto.h block: sed-opal: Set MBRDone on S3 resume path if TPER is MBREnabled 2017-09-11 09:45:52 -06:00
partition-generic.c block: return just one value from part_in_flight 2018-12-10 08:30:38 -07:00
scsi_ioctl.c block: consistently use GFP_NOIO instead of __GFP_NORECLAIM 2018-05-14 08:55:18 -06:00
sed-opal.c block: sed-opal: Fix a couple off by one bugs 2018-06-20 12:04:06 -06:00
t10-pi.c block: move dif_prepare/dif_complete functions to block layer 2018-07-30 08:27:02 -06:00