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Takashi Iwai 06a41a99d1 blk-mq: Fix uninitialized kobject at CPU hotplugging 
When a CPU is hotplugged, the current blk-mq spews a warning like:

  kobject '(null)' (ffffe8ffffc8b5d8): tried to add an uninitialized object, something is seriously wrong.
  CPU: 1 PID: 1386 Comm: systemd-udevd Not tainted 3.18.0-rc7-2.g088d59b-default #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_171129-lamiak 04/01/2014
   0000000000000000 0000000000000002 ffffffff81605f07 ffffe8ffffc8b5d8
   ffffffff8132c7a0 ffff88023341d370 0000000000000020 ffff8800bb05bd58
   ffff8800bb05bd08 000000000000a0a0 000000003f441940 0000000000000007
  Call Trace:
   [<ffffffff81005306>] dump_trace+0x86/0x330
   [<ffffffff81005644>] show_stack_log_lvl+0x94/0x170
   [<ffffffff81006d21>] show_stack+0x21/0x50
   [<ffffffff81605f07>] dump_stack+0x41/0x51
   [<ffffffff8132c7a0>] kobject_add+0xa0/0xb0
   [<ffffffff8130aee1>] blk_mq_register_hctx+0x91/0xb0
   [<ffffffff8130b82e>] blk_mq_sysfs_register+0x3e/0x60
   [<ffffffff81309298>] blk_mq_queue_reinit_notify+0xf8/0x190
   [<ffffffff8107cfdc>] notifier_call_chain+0x4c/0x70
   [<ffffffff8105fd23>] cpu_notify+0x23/0x50
   [<ffffffff81060037>] _cpu_up+0x157/0x170
   [<ffffffff810600d9>] cpu_up+0x89/0xb0
   [<ffffffff815fa5b5>] cpu_subsys_online+0x35/0x80
   [<ffffffff814323cd>] device_online+0x5d/0xa0
   [<ffffffff81432485>] online_store+0x75/0x80
   [<ffffffff81236a5a>] kernfs_fop_write+0xda/0x150
   [<ffffffff811c5532>] vfs_write+0xb2/0x1f0
   [<ffffffff811c5f42>] SyS_write+0x42/0xb0
   [<ffffffff8160c4ed>] system_call_fastpath+0x16/0x1b
   [<00007f0132fb24e0>] 0x7f0132fb24e0

This is indeed because of an uninitialized kobject for blk_mq_ctx.
The blk_mq_ctx kobjects are initialized in blk_mq_sysfs_init(), but it
goes loop over hctx_for_each_ctx(), i.e. it initializes only for
online CPUs.  Thus, when a CPU is hotplugged, the ctx for the newly
onlined CPU is registered without initialization.

This patch fixes the issue by initializing the all ctx kobjects
belonging to each queue.

Bugzilla: https://bugzilla.novell.com/show_bug.cgi?id=908794
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2014-12-10 08:57:31 -07:00
..
partitions block: Replace strnicmp with strncasecmp 2014-09-27 16:48:55 -06:00
bio-integrity.c bio-integrity: remove the needless fail handle of bip_slab creating 2014-10-13 15:09:38 -06:00
bio.c blk: introduce generic io stat accounting help function 2014-11-24 08:04:44 -07:00
blk-cgroup.c blkcg: remove blkcg->id 2014-09-08 09:55:37 -06:00
blk-cgroup.h blkcg: remove blkcg->id 2014-09-08 09:55:37 -06:00
blk-core.c blk-mq: Fix a use-after-free 2014-12-09 09:07:13 -07:00
blk-exec.c blk-mq: avoid infinite recursion with the FUA flag 2014-09-22 11:55:19 -06:00
blk-flush.c blk-mq: support per-distpatch_queue flush machinery 2014-09-25 15:22:45 -06:00
blk-integrity.c block: Don't merge requests if integrity flags differ 2014-09-27 09:14:57 -06:00
blk-ioc.c block: Substitute rcu_access_pointer() for rcu_dereference_raw() 2014-02-18 12:21:26 -08:00
blk-iopoll.c Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next 2014-06-03 12:57:53 -07:00
blk-lib.c block/blk-lib.c: make __blkdev_issue_zeroout static 2014-05-26 17:39:09 -06:00
blk-map.c block: remove struct request buffer member 2014-04-15 14:03:02 -06:00
blk-merge.c blk-merge: don't compute bi_phys_segments from bi_vcnt for cloned bio 2014-10-09 13:11:44 -06:00
blk-mq-cpu.c blk-mq: add file comments and update copyright notices 2014-05-28 10:15:41 -06:00
blk-mq-cpumap.c blk-mq: Use all available hardware queues 2014-12-09 09:08:21 -07:00
blk-mq-sysfs.c blk-mq: Fix uninitialized kobject at CPU hotplugging 2014-12-10 08:57:31 -07:00
blk-mq-tag.c blk-mq: Micro-optimize bt_get() 2014-12-09 09:07:28 -07:00
blk-mq-tag.h blk-mq: bitmap tag: fix races on shared ::wake_index fields 2014-06-17 22:12:35 -07:00
blk-mq.c blk-mq: prevent unmapped hw queue from being scheduled 2014-12-08 21:37:08 -07:00
blk-mq.h blk-mq: prevent unmapped hw queue from being scheduled 2014-12-08 21:37:08 -07:00
blk-settings.c block: remove artifical max_hw_sectors cap 2014-10-21 14:02:54 -06:00
blk-softirq.c block: fix regression with block enabled tagging 2014-04-09 21:54:06 -06:00
blk-sysfs.c blk-mq: Fix a use-after-free 2014-12-09 09:07:13 -07:00
blk-tag.c block: don't assume last put of shared tags is for the host 2014-07-08 12:25:28 +02:00
blk-throttle.c cgroup: remove sane_behavior support on non-default hierarchies 2014-07-09 10:08:08 -04:00
blk-timeout.c block: fix blk_abort_request on blk-mq 2014-09-22 12:00:08 -06:00
blk.h blk-mq: support per-distpatch_queue flush machinery 2014-09-25 15:22:45 -06:00
bounce.c mm: convert some level-less printks to pr_* 2014-06-06 16:08:18 -07:00
bsg-lib.c
bsg.c bsg: fix potential error pointer dereference 2014-08-29 08:34:14 -06:00
cfq-iosched.c Merge branch 'for-linus' into for-3.18/core 2014-09-11 09:31:18 -06:00
cmdline-parser.c
compat_ioctl.c block, bdi: an active gendisk always has a request_queue associated with it 2014-09-08 10:00:35 -06:00
deadline-iosched.c block: Stop abusing csd.list for fifo_time 2014-02-24 14:46:32 -08:00
elevator.c Revert "block: add __init to elv_register" 2014-06-22 16:34:11 -06:00
genhd.c genhd: check for int overflow in disk_expand_part_tbl() 2014-11-19 13:09:07 -07:00
ioctl.c block, bdi: an active gendisk always has a request_queue associated with it 2014-09-08 10:00:35 -06:00
ioprio.c block: move ioprio.c from fs/ to block/ 2014-05-19 11:02:18 -06:00
Kconfig block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00
Kconfig.iosched
Makefile block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00
noop-iosched.c
partition-generic.c block: Fix dev_t minor allocation lifetime 2014-09-03 15:01:02 -06:00
scsi_ioctl.c Merge branch 'for-linus' into for-3.18/core 2014-09-11 09:31:18 -06:00
t10-pi.c block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00