Shin'ichiro Kawasaki 6e0d24598c block: limit request dispatch loop duration ... commit 572299f03a upstream. When IO requests are made continuously and the target block device handles requests faster than request arrival, the request dispatch loop keeps on repeating to dispatch the arriving requests very long time, more than a minute. Since the loop runs as a workqueue worker task, the very long loop duration triggers workqueue watchdog timeout and BUG [1]. To avoid the very long loop duration, break the loop periodically. When opportunity to dispatch requests still exists, check need_resched(). If need_resched() returns true, the dispatch loop already consumed its time slice, then reschedule the dispatch work and break the loop. With heavy IO load, need_resched() does not return true for 20~30 seconds. To cover such case, check time spent in the dispatch loop with jiffies. If more than 1 second is spent, reschedule the dispatch work and break the loop. [1] [ 609.691437] BUG: workqueue lockup - pool cpus=10 node=1 flags=0x0 nice=-20 stuck for 35s! [ 609.701820] Showing busy workqueues and worker pools: [ 609.707915] workqueue events: flags=0x0 [ 609.712615] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 [ 609.712626] pending: drm_fb_helper_damage_work [drm_kms_helper] [ 609.712687] workqueue events_freezable: flags=0x4 [ 609.732943] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 [ 609.732952] pending: pci_pme_list_scan [ 609.732968] workqueue events_power_efficient: flags=0x80 [ 609.751947] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 [ 609.751955] pending: neigh_managed_work [ 609.752018] workqueue kblockd: flags=0x18 [ 609.769480] pwq 21: cpus=10 node=1 flags=0x0 nice=-20 active=3/256 refcnt=4 [ 609.769488] in-flight: 1020:blk_mq_run_work_fn [ 609.769498] pending: blk_mq_timeout_work, blk_mq_run_work_fn [ 609.769744] pool 21: cpus=10 node=1 flags=0x0 nice=-20 hung=35s workers=2 idle: 67 [ 639.899730] BUG: workqueue lockup - pool cpus=10 node=1 flags=0x0 nice=-20 stuck for 66s! [ 639.909513] Showing busy workqueues and worker pools: [ 639.915404] workqueue events: flags=0x0 [ 639.920197] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256 refcnt=2 [ 639.920215] pending: drm_fb_helper_damage_work [drm_kms_helper] [ 639.920365] workqueue kblockd: flags=0x18 [ 639.939932] pwq 21: cpus=10 node=1 flags=0x0 nice=-20 active=3/256 refcnt=4 [ 639.939942] in-flight: 1020:blk_mq_run_work_fn [ 639.939955] pending: blk_mq_timeout_work, blk_mq_run_work_fn [ 639.940212] pool 21: cpus=10 node=1 flags=0x0 nice=-20 hung=66s workers=2 idle: 67 Fixes: 6e6fcbc27e ("blk-mq: support batching dispatch in case of io") Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Cc: stable@vger.kernel.org # v5.10+ Link: https://lore.kernel.org/linux-block/20220310091649.zypaem5lkyfadymg@shindev/ Link: https://lore.kernel.org/r/20220318022641.133484-1-shinichiro.kawasaki@wdc.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2022-04-08 14:39:55 +02:00
..
partitions	partitions: msdos: fix one-byte get_unaligned()	2021-07-20 16:05:39 +02:00
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/wbt: fix negative inflight counter when remove scsi device	2022-02-23 12:01:04 +01:00
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: bio-integrity: Advance seed correctly for larger interval sizes	2022-02-08 18:30:35 +01:00
bio.c	block: Fix wrong offset in bio_truncate()	2022-02-01 17:25:48 +01:00
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: fix UAF by grabbing blkcg lock before destroying blkg pd	2021-09-30 10:11:07 +02:00
blk-core.c	blkcg: Remove extra blkcg_bio_issue_init	2021-11-26 10:39:13 +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	blk-crypto: fix check for too-large dun_bytes	2021-09-15 09:50:30 +02:00
blk-exec.c	block: add a blk_account_io_merge_bio helper	2020-05-27 05:21:23 -06:00
blk-flush.c	block: Fix fsync always failed if once failed	2022-01-27 10:54:30 +01:00
blk-integrity.c	block: flush the integrity workqueue in blk_integrity_unregister	2021-09-30 10:11:06 +02:00
blk-ioc.c	block: remove retry loop in ioc_release_fn()	2020-07-16 10:22:15 -06:00
blk-iocost.c	iocost: Fix divide-by-zero on donation from low hweight cgroup	2021-12-22 09:30:57 +01:00
blk-iolatency.c	blk-iolatency: error out if blk_get_queue() failed in iolatency_set_limit()	2021-08-12 13:22:08 +02:00
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: return ELEVATOR_DISCARD_MERGE if possible	2021-09-15 09:50:28 +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	block: decode QUEUE_FLAG_HCTX_ACTIVE in debugfs output	2021-10-27 09:56:46 +02:00
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	block: limit request dispatch loop duration	2022-04-08 14:39:55 +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: avoid to iterate over stale request	2021-09-30 10:11:05 +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	block: remove inaccurate requeue check	2021-11-18 14:03:58 +01:00
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: pm: Always set request queue runtime active in blk_post_runtime_resume()	2022-01-27 10:54:08 +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
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: fix UAF by deleteing timer in blk_throtl_exit()	2021-09-26 14:09:01 +02:00
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	blk-zoned: allow BLKREPORTZONE without CAP_SYS_ADMIN	2021-09-18 13:40:06 +02:00
blk.h	block: bump max plugged deferred size from 16 to 32	2021-11-18 14:03:57 +01:00
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	scsi: bsg: Remove support for SCSI_IOCTL_SEND_COMMAND	2021-09-18 13:40:11 +02:00
cmdline-parser.c
elevator.c	block/wbt: fix negative inflight counter when remove scsi device	2022-02-23 12:01:04 +01:00
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: fix ioprio_get(IOPRIO_WHO_PGRP) vs setuid(2)	2021-12-14 11:32:40 +01:00
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	block: return ELEVATOR_DISCARD_MERGE if possible	2021-09-15 09:50:28 +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