Jan Kara 8cc58a6e2c rq-qos: fix missed wake-ups in rq_qos_throttle try two ... commit 11c7aa0ddea8611007768d3e6b58d45dc60a19e1 upstream. Commit 545fbd0775 ("rq-qos: fix missed wake-ups in rq_qos_throttle") tried to fix a problem that a process could be sleeping in rq_qos_wait() without anyone to wake it up. However the fix is not complete and the following can still happen: CPU1 (waiter1) CPU2 (waiter2) CPU3 (waker) rq_qos_wait() rq_qos_wait() acquire_inflight_cb() -> fails acquire_inflight_cb() -> fails completes IOs, inflight decreased prepare_to_wait_exclusive() prepare_to_wait_exclusive() has_sleeper = !wq_has_single_sleeper() -> true as there are two sleepers has_sleeper = !wq_has_single_sleeper() -> true io_schedule() io_schedule() Deadlock as now there's nobody to wakeup the two waiters. The logic automatically blocking when there are already sleepers is really subtle and the only way to make it work reliably is that we check whether there are some waiters in the queue when adding ourselves there. That way, we are guaranteed that at least the first process to enter the wait queue will recheck the waiting condition before going to sleep and thus guarantee forward progress. Fixes: 545fbd0775 ("rq-qos: fix missed wake-ups in rq_qos_throttle") CC: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20210607112613.25344-1-jack@suse.cz Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-07-19 09:45:00 +02:00
..
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	kyber: fix out of bounds access when preempted	2021-05-19 10:13:13 +02:00
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: only update parent bi_status when bio fail	2021-04-16 11:43:21 +02:00
blk-cgroup-rwstat.c	blk-cgroup: Fix the recursive blkg rwstat	2021-03-30 14:31:48 +02:00
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: Use cond_resched() when destroy blkgs	2021-02-13 13:55:13 +01:00
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: avoid double io accounting for flush request	2021-07-14 16:56:11 +02:00
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 weight updates of inner active iocgs	2021-05-19 10:13:11 +02:00
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	block: fix discard request merge	2021-07-14 16:56:02 +02:00
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	blk-mq-debugfs: Add decode for BLK_MQ_F_TAG_HCTX_SHARED	2021-01-19 18:27:29 +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	kyber: fix out of bounds access when preempted	2021-05-19 10:13:13 +02:00
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	blk-mq: clear stale request in tags->rq[] before freeing one request pool	2021-07-14 16:55:58 +02:00
blk-mq-tag.h	blk-mq: clear stale request in tags->rq[] before freeing one request pool	2021-07-14 16:55:58 +02:00
blk-mq-virtio.c	blk-mq: Fix typo in comment	2020-03-17 20:55:21 +01:00
blk-mq.c	blk-mq: update hctx->dispatch_busy in case of real scheduler	2021-07-14 16:56:13 +02:00
blk-mq.h	blk-mq: grab rq->refcount before calling ->fn in blk_mq_tagset_busy_iter	2021-07-14 16:55:58 +02:00
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	rq-qos: fix missed wake-ups in rq_qos_throttle try two	2021-07-19 09:45:00 +02:00
blk-rq-qos.h	block: fix race between adding/removing rq qos and normal IO	2021-07-14 16:56:00 +02:00
blk-settings.c	blk-settings: align max_sectors on "logical_block_size" boundary	2021-03-04 11:38:22 +01:00
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	blk-wbt: make sure throttle is enabled properly	2021-07-14 16:56:12 +02:00
blk-wbt.h	blk-wbt: introduce a new disable state to prevent false positive by rwb_enabled()	2021-07-14 16:56:12 +02:00
blk-zoned.c	block: Fix REQ_OP_ZONE_RESET_ALL handling	2021-03-30 14:31:51 +02:00
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	bsg: free the request before return error code	2021-03-04 11:37:42 +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: Suppress uevent for hidden device when removed	2021-03-30 14:31:52 +02:00
ioctl.c	block: return -EBUSY when there are open partitions in blkdev_reread_part	2021-04-28 13:39:59 +02:00
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	kyber: fix out of bounds access when preempted	2021-05-19 10:13:13 +02:00
Makefile	blk-mq: merge blk-softirq.c into blk-mq.c	2020-06-24 09:15:56 -06:00
mq-deadline.c	kyber: fix out of bounds access when preempted	2021-05-19 10:13:13 +02:00
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