linux_dsm_epyc7002/block
Tejun Heo cafc6e70a6 blk-iocost: fix NULL iocg deref from racing against initialization
commit d16baa3f1453c14d680c5fee01cd122a22d0e0ce upstream.

When initializing iocost for a queue, its rqos should be registered before
the blkcg policy is activated to allow policy data initiailization to lookup
the associated ioc. This unfortunately means that the rqos methods can be
called on bios before iocgs are attached to all existing blkgs.

While the race is theoretically possible on ioc_rqos_throttle(), it mostly
happened in ioc_rqos_merge() due to the difference in how they lookup ioc.
The former determines it from the passed in @rqos and then bails before
dereferencing iocg if the looked up ioc is disabled, which most likely is
the case if initialization is still in progress. The latter looked up ioc by
dereferencing the possibly NULL iocg making it a lot more prone to actually
triggering the bug.

* Make ioc_rqos_merge() use the same method as ioc_rqos_throttle() to look
  up ioc for consistency.

* Make ioc_rqos_throttle() and ioc_rqos_merge() test for NULL iocg before
  dereferencing it.

* Explain the danger of NULL iocgs in blk_iocost_init().

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Jonathan Lemon <bsd@fb.com>
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-12 20:18:23 +01:00
..
partitions block-5.10-2020-10-12 2020-10-13 12:12:44 -07:00
badblocks.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
bfq-cgroup.c bfq: fix blkio cgroup leakage v4 2020-08-18 07:48:08 -07:00
bfq-iosched.c block-5.10-2020-10-12 2020-10-13 12:12:44 -07:00
bfq-iosched.h bfq: fix blkio cgroup leakage v4 2020-08-18 07:48:08 -07:00
bfq-wf2q.c bfq: fix blkio cgroup leakage v4 2020-08-18 07:48:08 -07:00
bio-integrity.c block: make function __bio_integrity_free() static 2020-07-02 12:38:18 -06:00
bio.c block: advance iov_iter on bio_add_hw_page failure 2020-10-28 07:51:02 -06:00
blk-cgroup-rwstat.c blk-cgroup: separate out blkg_rwstat under CONFIG_BLK_CGROUP_RWSTAT 2019-11-07 12:28:13 -07:00
blk-cgroup-rwstat.h blk-cgroup: separate out blkg_rwstat under CONFIG_BLK_CGROUP_RWSTAT 2019-11-07 12:28:13 -07:00
blk-cgroup.c blk-cgroup: fix a hd_struct leak in blkcg_fill_root_iostats 2020-11-14 11:17:34 -07:00
blk-core.c scsi: block: Do not accept any requests while suspended 2021-01-12 20:18:17 +01:00
blk-crypto-fallback.c block: rename generic_make_request to submit_bio_noacct 2020-07-01 07:27:24 -06:00
blk-crypto-internal.h block: make blk_crypto_rq_bio_prep() able to fail 2020-10-05 10:47:43 -06:00
blk-crypto.c block: warn if !__GFP_DIRECT_RECLAIM in bio_crypt_set_ctx() 2020-10-05 10:47:43 -06:00
blk-exec.c block: add a blk_account_io_merge_bio helper 2020-05-27 05:21:23 -06:00
blk-flush.c block: mark flush request as IDLE when it is really finished 2020-11-13 14:24:16 -07:00
blk-integrity.c block: remove the unused blk_integrity_merge_bio export 2020-10-06 07:29:53 -06:00
blk-ioc.c block: remove retry loop in ioc_release_fn() 2020-07-16 10:22:15 -06:00
blk-iocost.c blk-iocost: fix NULL iocg deref from racing against initialization 2021-01-12 20:18:23 +01:00
blk-iolatency.c block: Remove redundant 'return' statement 2020-10-08 07:59:48 -06:00
blk-lib.c block: add a bdev_is_partition helper 2020-09-25 08:18:57 -06:00
blk-map.c block: fix bmd->is_null_mapped initialization 2020-09-23 09:18:39 -06:00
blk-merge.c dm: fix IO splitting 2020-12-04 14:53:15 -05:00
blk-mq-cpumap.c blk-mq: remove the calling of local_memory_node() 2020-10-20 07:08:17 -06:00
blk-mq-debugfs-zoned.c block: Cleanup license notice 2019-01-17 21:21:40 -07:00
blk-mq-debugfs.c scsi: block: Remove RQF_PREEMPT and BLK_MQ_REQ_PREEMPT 2021-01-12 20:18:17 +01:00
blk-mq-debugfs.h blk-mq: no need to check return value of debugfs_create functions 2019-06-13 03:00:30 -06:00
blk-mq-pci.c block: Fix blk_mq_*_map_queues() kernel-doc headers 2019-05-31 15:12:34 -06:00
blk-mq-rdma.c block: Fix blk_mq_*_map_queues() kernel-doc headers 2019-05-31 15:12:34 -06:00
blk-mq-sched.c blk-mq: get rid of the dead flush handle code path 2020-10-09 12:35:39 -06:00
blk-mq-sched.h block-5.10-2020-10-12 2020-10-13 12:12:44 -07:00
blk-mq-sysfs.c blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue 2020-10-09 12:46:28 -06:00
blk-mq-tag.c block-mq: fix comments in blk_mq_queue_tag_busy_iter 2020-09-29 08:11:00 -06:00
blk-mq-tag.h blk-mq: Relocate hctx_may_queue() 2020-09-03 15:20:47 -06:00
blk-mq-virtio.c blk-mq: Fix typo in comment 2020-03-17 20:55:21 +01:00
blk-mq.c scsi: block: Remove RQF_PREEMPT and BLK_MQ_REQ_PREEMPT 2021-01-12 20:18:17 +01:00
blk-mq.h blk-mq: Record active_queues_shared_sbitmap per tag_set for when using shared sbitmap 2020-09-03 15:20:47 -06:00
blk-pm.c scsi: block: Fix a race in the runtime power management code 2021-01-06 14:56:50 +01:00
blk-pm.h scsi: block: Do not accept any requests while suspended 2021-01-12 20:18:17 +01:00
blk-rq-qos.c Revert "blk-rq-qos: remove redundant finish_wait to rq_qos_wait." 2020-07-15 09:33:37 -06:00
blk-rq-qos.h blk-rq-qos: fix first node deletion of rq_qos_del() 2019-10-15 10:13:13 -06:00
blk-settings.c block: use gcd() to fix chunk_sectors limit stacking 2020-12-01 11:02:55 -07:00
blk-stat.c blk-stat: make q->stats->lock irqsafe 2020-09-01 16:48:46 -06:00
blk-stat.h block: deactivate blk_stat timer in wbt_disable_default() 2018-12-12 06:47:51 -07:00
blk-sysfs.c blk-mq: move cancel of hctx->run_work to the front of blk_exit_queue 2020-10-09 12:46:28 -06:00
blk-throttle.c blk-throttle: Re-use the throtl_set_slice_end() 2020-10-08 08:01:38 -06:00
blk-timeout.c block: blk-timeout: delete duplicated word 2020-07-31 16:29:47 -06:00
blk-wbt.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
blk-wbt.h blk-wbt: remove wbt_update_limits 2020-05-29 16:30:39 -06:00
blk-zoned.c block: don't do revalidate zones on invalid devices 2020-08-03 09:24:04 -06:00
blk.h block: move blk_mq_sched_try_merge to blk-merge.c 2020-10-06 07:29:53 -06:00
bounce.c block: make bio_crypt_clone() able to fail 2020-10-05 10:47:43 -06:00
bsg-lib.c block: drop double zeroing 2020-09-23 09:18:13 -06:00
bsg.c compat_ioctl: bsg: add handler 2020-01-03 09:33:21 +01:00
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
elevator.c block: fix comment and add lockdep assert 2020-10-09 12:34:06 -06:00
genhd.c block: add a return value to set_capacity_revalidate_and_notify 2020-11-12 13:59:04 -07:00
ioctl.c block: add a bdev_is_partition helper 2020-09-25 08:18:57 -06:00
ioprio.c block: grant IOPRIO_CLASS_RT to CAP_SYS_NICE 2020-09-01 19:38:33 -06:00
Kconfig blk-wbt: Remove obsolete multiqueue I/O scheduling comment 2020-09-01 16:49:26 -06:00
Kconfig.iosched treewide: replace '---help---' in Kconfig files with 'help' 2020-06-14 01:57:21 +09:00
keyslot-manager.c block/keyslot-manager: prevent crash when num_slots=1 2020-11-20 11:52:52 -07:00
kyber-iosched.c blk-mq: Use pointers for blk_mq_tags bitmap tags 2020-09-03 15:20:47 -06:00
Makefile blk-mq: merge blk-softirq.c into blk-mq.c 2020-06-24 09:15:56 -06:00
mq-deadline.c blk-mq, elevator: Count requests per hctx to improve performance 2020-09-03 15:20:47 -06:00
opal_proto.h block: sed-opal: Change the check condition for regular session validity 2020-03-12 08:00:10 -06:00
scsi_ioctl.c drivers-5.10-2020-10-12 2020-10-13 13:04:41 -07:00
sed-opal.c block: sed-opal: Change the check condition for regular session validity 2020-03-12 08:00:10 -06:00
t10-pi.c block: Allow t10-pi to be modular 2020-01-06 20:59:04 -07:00