Dennis Zhou 0fe061b9f0 blkcg: fix ref count issue with bio_blkcg() using task_css ... The bio_blkcg() function turns out to be inconsistent and consequently dangerous to use. The first part returns a blkcg where a reference is owned by the bio meaning it does not need to be rcu protected. However, the third case, the last line, is problematic: return css_to_blkcg(task_css(current, io_cgrp_id)); This can race against task migration and the cgroup dying. It is also semantically different as it must be called rcu protected and is susceptible to failure when trying to get a reference to it. This patch adds association ahead of calling bio_blkcg() rather than after. This makes association a required and explicit step along the code paths for calling bio_blkcg(). In blk-iolatency, association is moved above the bio_blkcg() call to ensure it will not return %NULL. BFQ uses the old bio_blkcg() function, but I do not want to address it in this series due to the complexity. I have created a private version documenting the inconsistency and noting not to use it. Signed-off-by: Dennis Zhou <dennis@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>		2018-12-07 22:26:36 -07:00
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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	blkcg: fix ref count issue with bio_blkcg() using task_css	2018-12-07 22:26:36 -07:00
bfq-iosched.h	block, bfq: improve asymmetric scenarios detection	2018-10-13 15:40:00 -06:00
bfq-wf2q.c	block, bfq: fix asymmetric scenarios detection	2018-10-25 11:17:40 -06:00
bio-integrity.c	block: remove bio_rewind_iter()	2018-09-06 15:12:24 -06:00
bio.c	blkcg: fix ref count issue with bio_blkcg() using task_css	2018-12-07 22:26:36 -07:00
blk-cgroup.c	block: add queue_is_mq() helper	2018-11-16 08:34:06 -07:00
blk-core.c	block: remove ->poll_fn	2018-12-04 11:38:19 -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	blkcg: fix ref count issue with bio_blkcg() using task_css	2018-12-07 22:26:36 -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	Linux 4.20-rc5	2018-12-04 09:38:05 -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: enable polling by default if a poll map is initalized	2018-12-04 11:38:19 -07:00
blk-mq.h	block: move queues types to the block layer	2018-12-04 11:38:17 -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	blk-rq-qos: inline check for q->rq_qos functions	2018-11-16 08:34:19 -07:00
blk-rq-qos.h	blk-rq-qos: inline check for q->rq_qos functions	2018-11-16 08:34:19 -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	blk-stat: export helpers for modifying blk_rq_stat	2018-07-09 09:07:54 -06:00
blk-sysfs.c	block: only allow polling if a poll queue_map exists	2018-12-04 11:38:19 -07:00
blk-throttle.c	block: add queue_is_mq() helper	2018-11-16 08:34:06 -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: add queue_is_mq() helper	2018-11-16 08:34:06 -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	block: copy ioprio in __bio_clone_fast() and bounce	2018-11-12 10:35:25 -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: add queue_is_mq() helper	2018-11-16 08:34:06 -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: use rcu_work instead of call_rcu to avoid sleep in softirq	2018-11-28 09:08:27 -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