Commit 16f5dfbc85 ("gfp: include __GFP_NOWARN in GFP_NOWAIT") made
GFP_NOWAIT implicitly include __GFP_NOWARN.
Therefore, explicit __GFP_NOWARN combined with GFP_NOWAIT (e.g.,
`GFP_NOWAIT | __GFP_NOWARN`) is now redundant. Let's clean up these
redundant flags across subsystems.
Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20250809141358.168781-1-rongqianfeng@vivo.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
- cgroup rstat shared the tracking tree across all controlers with the
rationale being that a cgroup which is using one resource is likely to be
using other resources at the same time (ie. if something is allocating
memory, it's probably consuming CPU cycles). However, this turned out to
not scale very well especially with memcg using rstat for internal
operations which made memcg stat read and flush patterns substantially
different from other controllers. JP Kobryn split the rstat tree per
controller.
- cgroup BPF support was hooking into cgroup init/exit paths directly.
Convert them to use a notifier chain instead so that other usages can be
added easily. The two of the patches which implement this are mislabeled
as belonging to sched_ext instead of cgroup. Sorry.
- Relatively minor cpuset updates.
- Documentation updates.
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Merge tag 'cgroup-for-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
- cgroup rstat shared the tracking tree across all controllers with the
rationale being that a cgroup which is using one resource is likely
to be using other resources at the same time (ie. if something is
allocating memory, it's probably consuming CPU cycles).
However, this turned out to not scale very well especially with memcg
using rstat for internal operations which made memcg stat read and
flush patterns substantially different from other controllers. JP
Kobryn split the rstat tree per controller.
- cgroup BPF support was hooking into cgroup init/exit paths directly.
Convert them to use a notifier chain instead so that other usages can
be added easily. The two of the patches which implement this are
mislabeled as belonging to sched_ext instead of cgroup. Sorry.
- Relatively minor cpuset updates
- Documentation updates
* tag 'cgroup-for-6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (23 commits)
sched_ext: Convert cgroup BPF support to use cgroup_lifetime_notifier
sched_ext: Introduce cgroup_lifetime_notifier
cgroup: Minor reorganization of cgroup_create()
cgroup, docs: cpu controller's interaction with various scheduling policies
cgroup, docs: convert space indentation to tab indentation
cgroup: avoid per-cpu allocation of size zero rstat cpu locks
cgroup, docs: be specific about bandwidth control of rt processes
cgroup: document the rstat per-cpu initialization
cgroup: helper for checking rstat participation of css
cgroup: use subsystem-specific rstat locks to avoid contention
cgroup: use separate rstat trees for each subsystem
cgroup: compare css to cgroup::self in helper for distingushing css
cgroup: warn on rstat usage by early init subsystems
cgroup/cpuset: drop useless cpumask_empty() in compute_effective_exclusive_cpumask()
cgroup/rstat: Improve cgroup_rstat_push_children() documentation
cgroup: fix goto ordering in cgroup_init()
cgroup: fix pointer check in css_rstat_init()
cgroup/cpuset: Add warnings to catch inconsistency in exclusive CPUs
cgroup/cpuset: Fix obsolete comment in cpuset_css_offline()
cgroup/cpuset: Always use cpu_active_mask
...
It is possible to eliminate contention between subsystems when
updating/flushing stats by using subsystem-specific locks. Let the existing
rstat locks be dedicated to the cgroup base stats and rename them to
reflect that. Add similar locks to the cgroup_subsys struct for use with
individual subsystems.
Lock initialization is done in the new function ss_rstat_init(ss) which
replaces cgroup_rstat_boot(void). If NULL is passed to this function, the
global base stat locks will be initialized. Otherwise, the subsystem locks
will be initialized.
Change the existing lock helper functions to accept a reference to a css.
Then within these functions, conditionally select the appropriate locks
based on the subsystem affiliation of the given css. Add helper functions
for this selection routine to avoid repeated code.
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Loading a driver just to configure blk-cgroup doesn't make sense, as that
assumes and already existing device.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20250423053810.1683309-5-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blkdev_get_no_open can trigger the legacy autoload of block drivers. A
simple stat of a block device has not historically done that, so disable
this behavior again.
Fixes: 9abcfbd235 ("block: Add atomic write support for statx")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20250423053810.1683309-4-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This non-functional change serves as preparation for moving to
subsystem-based rstat trees. To simplify future commits, change the
signatures of existing cgroup-based rstat functions to become css-based and
rename them to reflect that.
Though the signatures have changed, the implementations have not. Within
these functions use the css->cgroup pointer to obtain the associated cgroup
and allow code to function the same just as it did before this patch. At
applicable call sites, pass the subsystem-specific css pointer as an
argument or pass a pointer to cgroup::self if not in subsystem context.
Note that cgroup_rstat_updated_list() and cgroup_rstat_push_children()
are not altered yet since there would be a larger amount of css to
cgroup conversions which may overcomplicate the code at this
intermediate phase.
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
- Add deprecation info messages to cgroup1-only features.
- rstat updates including a bug fix and breaking up a critical section to
reduce interrupt latency impact.
- Other misc and doc updates.
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Merge tag 'cgroup-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
- Add deprecation info messages to cgroup1-only features
- rstat updates including a bug fix and breaking up a critical section
to reduce interrupt latency impact
- Other misc and doc updates
* tag 'cgroup-for-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: rstat: Cleanup flushing functions and locking
cgroup/rstat: avoid disabling irqs for O(num_cpu)
mm: Fix a build breakage in memcontrol-v1.c
blk-cgroup: Simplify policy files registration
cgroup: Update file naming comment
cgroup: Add deprecation message to legacy freezer controller
mm: Add transformation message for per-memcg swappiness
RFC cgroup/cpuset-v1: Add deprecation messages to sched_relax_domain_level
cgroup/cpuset-v1: Add deprecation messages to memory_migrate
cgroup/cpuset-v1: Add deprecation messages to mem_exclusive and mem_hardwall
cgroup: Print message when /proc/cgroups is read on v2-only system
cgroup/blkio: Add deprecation messages to reset_stats
cgroup/cpuset-v1: Add deprecation messages to memory_spread_page and memory_spread_slab
cgroup/cpuset-v1: Add deprecation messages to sched_load_balance and memory_pressure_enabled
cgroup, docs: Be explicit about independence of RT_GROUP_SCHED and non-cpu controllers
cgroup/rstat: Fix forceidle time in cpu.stat
cgroup/misc: Remove unused misc_cg_res_total_usage
cgroup/cpuset: Move procfs cpuset attribute under cgroup-v1.c
cgroup: update comment about dropping cgroup kn refs
The commit '245618f8e45f ("block: protect wbt_lat_usec using q->
elevator_lock")' introduced q->elevator_lock to protect updates
to blk-wbt parameters when writing to the sysfs attribute wbt_
lat_usec and the cgroup attribute io.cost.qos. However, both
these attributes also acquire q->rq_qos_mutex, leading to the
following lockdep warning:
======================================================
WARNING: possible circular locking dependency detected
6.14.0-rc5+ #138 Not tainted
------------------------------------------------------
bash/5902 is trying to acquire lock:
c000000085d495a0 (&q->rq_qos_mutex){+.+.}-{4:4}, at: wbt_init+0x164/0x238
but task is already holding lock:
c000000085d498c8 (&q->elevator_lock){+.+.}-{4:4}, at: queue_wb_lat_store+0xb0/0x20c
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&q->elevator_lock){+.+.}-{4:4}:
__mutex_lock+0xf0/0xa58
ioc_qos_write+0x16c/0x85c
cgroup_file_write+0xc4/0x32c
kernfs_fop_write_iter+0x1b8/0x29c
vfs_write+0x410/0x584
ksys_write+0x84/0x140
system_call_exception+0x134/0x360
system_call_vectored_common+0x15c/0x2ec
-> #0 (&q->rq_qos_mutex){+.+.}-{4:4}:
__lock_acquire+0x1b6c/0x2ae0
lock_acquire+0x140/0x430
__mutex_lock+0xf0/0xa58
wbt_init+0x164/0x238
queue_wb_lat_store+0x1dc/0x20c
queue_attr_store+0x12c/0x164
sysfs_kf_write+0x6c/0xb0
kernfs_fop_write_iter+0x1b8/0x29c
vfs_write+0x410/0x584
ksys_write+0x84/0x140
system_call_exception+0x134/0x360
system_call_vectored_common+0x15c/0x2ec
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&q->elevator_lock);
lock(&q->rq_qos_mutex);
lock(&q->elevator_lock);
lock(&q->rq_qos_mutex);
*** DEADLOCK ***
6 locks held by bash/5902:
#0: c000000051122400 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x84/0x140
#1: c00000007383f088 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x174/0x29c
#2: c000000008550428 (kn->active#182){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x180/0x29c
#3: c000000085d493a8 (&q->q_usage_counter(io)#5){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x28/0x40
#4: c000000085d493e0 (&q->q_usage_counter(queue)#5){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x28/0x40
#5: c000000085d498c8 (&q->elevator_lock){+.+.}-{4:4}, at: queue_wb_lat_store+0xb0/0x20c
stack backtrace:
CPU: 17 UID: 0 PID: 5902 Comm: bash Kdump: loaded Not tainted 6.14.0-rc5+ #138
Hardware name: IBM,9043-MRX POWER10 (architected) 0x800200 0xf000006 of:IBM,FW1060.00 (NM1060_028) hv:phyp pSeries
Call Trace:
[c0000000721ef590] [c00000000118f8a8] dump_stack_lvl+0x108/0x18c (unreliable)
[c0000000721ef5c0] [c00000000022563c] print_circular_bug+0x448/0x604
[c0000000721ef670] [c000000000225a44] check_noncircular+0x24c/0x26c
[c0000000721ef740] [c00000000022bf28] __lock_acquire+0x1b6c/0x2ae0
[c0000000721ef870] [c000000000229240] lock_acquire+0x140/0x430
[c0000000721ef970] [c0000000011cfbec] __mutex_lock+0xf0/0xa58
[c0000000721efaa0] [c00000000096c46c] wbt_init+0x164/0x238
[c0000000721efaf0] [c0000000008f8cd8] queue_wb_lat_store+0x1dc/0x20c
[c0000000721efb50] [c0000000008f8fa0] queue_attr_store+0x12c/0x164
[c0000000721efc60] [c0000000007c11cc] sysfs_kf_write+0x6c/0xb0
[c0000000721efca0] [c0000000007bfa4c] kernfs_fop_write_iter+0x1b8/0x29c
[c0000000721efcf0] [c0000000006a281c] vfs_write+0x410/0x584
[c0000000721efdc0] [c0000000006a2cc8] ksys_write+0x84/0x140
[c0000000721efe10] [c000000000031b64] system_call_exception+0x134/0x360
[c0000000721efe50] [c00000000000cedc] system_call_vectored_common+0x15c/0x2ec
>From the above log it's apparent that method which writes to sysfs attr
wbt_lat_usec acquires q->elevator_lock first, and then acquires q->rq_
qos_mutex. However the another method which writes to io.cost.qos,
acquires q->rq_qos_mutex first, and then acquires q->rq_qos_mutex. So
this could potentially cause the deadlock.
A closer look at ioc_qos_write shows that correcting the lock order is
non-trivial because q->rq_qos_mutex is acquired in blkg_conf_open_bdev
and released in blkg_conf_exit. The function blkg_conf_open_bdev is
responsible for parsing user input and finding the corresponding block
device (bdev) from the user provided major:minor number.
Since we do not know the bdev until blkg_conf_open_bdev completes, we
cannot simply move q->elevator_lock acquisition before blkg_conf_open_
bdev. So to address this, we intoduce new helpers blkg_conf_open_bdev_
frozen and blkg_conf_exit_frozen which are just wrappers around blkg_
conf_open_bdev and blkg_conf_exit respectively. The helper blkg_conf_
open_bdev_frozen is similar to blkg_conf_open_bdev, but additionally
freezes the queue, acquires q->elevator_lock and ensures the correct
locking order is followed between q->elevator_lock and q->rq_qos_mutex.
Similarly another helper blkg_conf_exit_frozen in addition to unfreezing
the queue ensures that we release the locks in correct order.
By using these helpers, now we maintain the same locking order in all
code paths where we update blk-wbt parameters.
Fixes: 245618f8e4 ("block: protect wbt_lat_usec using q->elevator_lock")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202503171650.cc082b66-lkp@intel.com
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Link: https://lore.kernel.org/r/20250319105518.468941-3-nilay@linux.ibm.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This patch improve the returned error code of blkcg_policy_register().
1. Move the validation check for cpd/pd_alloc_fn and cpd/pd_free_fn
function pairs to the start of blkcg_policy_register(). This ensures
we immediately return -EINVAL if the function pairs are not correctly
provided, rather than returning -ENOSPC after locking and unlocking
mutexes unnecessarily.
Those locks should not contention any problems, as error of policy
registration is a super cold path.
2. Return -ENOMEM when cpd_alloc_fn() failed.
Co-authored-by: Wen Tao <wentao@uniontech.com>
Signed-off-by: Wen Tao <wentao@uniontech.com>
Signed-off-by: Chen Linxuan <chenlinxuan@uniontech.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/3E333A73B6B6DFC0+20250317022924.150907-1-chenlinxuan@uniontech.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use one set of files when there is no difference between default and
legacy files, similar to regular subsys files registration. No
functional change.
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Tejun Heo <tj@kernel.org>
It is difficult to sync with stat updaters, stats are (should be)
monotonic so users can calculate differences from a reference.
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Merge tag 'block-6.14-20250131' of git://git.kernel.dk/linux
Pull more block updates from Jens Axboe:
- MD pull request via Song:
- Fix a md-cluster regression introduced
- More sysfs race fixes
- Mark anything inside queue freezing as not being able to do IO for
memory allocations
- Fix for a regression introduced in loop in this merge window
- Fix for a regression in queue mapping setups introduced in this merge
window
- Fix for the block dio fops attempting an iov_iter revert upton
getting -EIOCBQUEUED on the read side. This one is going to stable as
well
* tag 'block-6.14-20250131' of git://git.kernel.dk/linux:
block: force noio scope in blk_mq_freeze_queue
block: fix nr_hw_queue update racing with disk addition/removal
block: get rid of request queue ->sysfs_dir_lock
loop: don't clear LO_FLAGS_PARTSCAN on LOOP_SET_STATUS{,64}
md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime
blk-mq: create correct map for fallback case
block: don't revert iter for -EIOCBQUEUED
When block drivers or the core block code perform allocations with a
frozen queue, this could try to recurse into the block device to
reclaim memory and deadlock. Thus all allocations done by a process
that froze a queue need to be done without __GFP_IO and __GFP_FS.
Instead of tying to track all of them down, force a noio scope as
part of freezing the queue.
Note that nvme is a bit of a mess here due to the non-owner freezes,
and they will be addressed separately.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20250131120352.1315351-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blkcg_fill_root_iostats() iterates over @block_class's devices by
class_dev_iter_(init|next)(), but does not end iterating with
class_dev_iter_exit(), so causes the class's subsystem refcount leakage.
Fix by ending the iterating with class_dev_iter_exit().
Fixes: ef45fe470e ("blk-cgroup: show global disk stats in root cgroup io.stat")
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Link: https://lore.kernel.org/r/20250105-class_fix-v6-2-3a2f1768d4d4@quicinc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
blkcg_unpin_online() walks up the blkcg hierarchy putting the online pin. To
walk up, it uses blkcg_parent(blkcg) but it was calling that after
blkcg_destroy_blkgs(blkcg) which could free the blkcg, leading to the
following UAF:
==================================================================
BUG: KASAN: slab-use-after-free in blkcg_unpin_online+0x15a/0x270
Read of size 8 at addr ffff8881057678c0 by task kworker/9:1/117
CPU: 9 UID: 0 PID: 117 Comm: kworker/9:1 Not tainted 6.13.0-rc1-work-00182-gb8f52214c61a-dirty #48
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS unknown 02/02/2022
Workqueue: cgwb_release cgwb_release_workfn
Call Trace:
<TASK>
dump_stack_lvl+0x27/0x80
print_report+0x151/0x710
kasan_report+0xc0/0x100
blkcg_unpin_online+0x15a/0x270
cgwb_release_workfn+0x194/0x480
process_scheduled_works+0x71b/0xe20
worker_thread+0x82a/0xbd0
kthread+0x242/0x2c0
ret_from_fork+0x33/0x70
ret_from_fork_asm+0x1a/0x30
</TASK>
...
Freed by task 1944:
kasan_save_track+0x2b/0x70
kasan_save_free_info+0x3c/0x50
__kasan_slab_free+0x33/0x50
kfree+0x10c/0x330
css_free_rwork_fn+0xe6/0xb30
process_scheduled_works+0x71b/0xe20
worker_thread+0x82a/0xbd0
kthread+0x242/0x2c0
ret_from_fork+0x33/0x70
ret_from_fork_asm+0x1a/0x30
Note that the UAF is not easy to trigger as the free path is indirected
behind a couple RCU grace periods and a work item execution. I could only
trigger it with artifical msleep() injected in blkcg_unpin_online().
Fix it by reading the parent pointer before destroying the blkcg's blkg's.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Abagail ren <renzezhongucas@gmail.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Fixes: 4308a434e5 ("blkcg: don't offline parent blkcg first")
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
ioprio works on the blk-cgroup level, all disks in the same cgroup
are the same, and the struct ioprio_blkg doesn't have anything in it.
Hence register the policy is enough, because cpd_alloc/free_fn will
be handled for each blk-cgroup, and there is no need to activate the
policy for disk. Hence remove blk_ioprio_init/exit and
ioprio_alloc/free_pd.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20240719071506.158075-4-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Currently all policies implement pd_(alloc|free)_fn, however, this is
not necessary for ioprio that only works for blkcg, not blkg.
There are no functional changes, prepare to cleanup activating ioprio
policy.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20240719071506.158075-2-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The congestion_count was introduced into the struct cgroup by
commit d09d8df3a2 ("blkcg: add generic throttling mechanism"),
but since it is closely related to the blkio subsys, it is not
appropriate to put it in the struct cgroup, so let's move it to
struct blkcg. There should be no functional changes because blkcg
is per cgroup.
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20240716133058.3491350-1-xiujianfeng@huawei.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
During a cgroup_rstat_flush() call, the lowest level of nodes are flushed
first before their parents. Since commit 3b8cc62987 ("blk-cgroup:
Optimize blkcg_rstat_flush()"), iostat propagation was still done to
the parent. Grandparent, however, may not get the iostat update if the
parent has no blkg_iostat_set queued in its lhead lockless list.
Fix this iostat propagation problem by queuing the parent's global
blkg->iostat into one of its percpu lockless lists to make sure that
the delta will always be propagated up to the grandparent and so on
toward the root blkcg.
Note that successive calls to __blkcg_rstat_flush() are serialized by
the cgroup_rstat_lock. So no special barrier is used in the reading
and writing of blkg->iostat.lqueued.
Fixes: 3b8cc62987 ("blk-cgroup: Optimize blkcg_rstat_flush()")
Reported-by: Dan Schatzberg <schatzberg.dan@gmail.com>
Closes: https://lore.kernel.org/lkml/ZkO6l%2FODzadSgdhC@dschatzberg-fedora-PF3DHTBV/
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20240515143059.276677-1-longman@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
__blkcg_rstat_flush() can be run anytime, especially when blk_cgroup_bio_start
is being executed.
If WRITE of `->lqueued` is re-ordered with READ of 'bisc->lnode.next' in
the loop of __blkcg_rstat_flush(), `next_bisc` can be assigned with one
stat instance being added in blk_cgroup_bio_start(), then the local
list in __blkcg_rstat_flush() could be corrupted.
Fix the issue by adding one barrier.
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Fixes: 3b8cc62987 ("blk-cgroup: Optimize blkcg_rstat_flush()")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20240515013157.443672-3-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since commit 3b8cc62987 ("blk-cgroup: Optimize blkcg_rstat_flush()"),
each iostat instance is added to blkcg percpu list, so blkcg_reset_stats()
can't reset the stat instance by memset(), otherwise the llist may be
corrupted.
Fix the issue by only resetting the counter part.
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Jay Shin <jaeshin@redhat.com>
Fixes: 3b8cc62987 ("blk-cgroup: Optimize blkcg_rstat_flush()")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20240515013157.443672-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-6.10/block-20240511' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- Add a partscan attribute in sysfs, fixing an issue with systemd
relying on an internal interface that went away.
- Attempt #2 at making long running discards interruptible. The
previous attempt went into 6.9, but we ended up mostly reverting it
as it had issues.
- Remove old ida_simple API in bcache
- Support for zoned write plugging, greatly improving the performance
on zoned devices.
- Remove the old throttle low interface, which has been experimental
since 2017 and never made it beyond that and isn't being used.
- Remove page->index debugging checks in brd, as it hasn't caught
anything and prepares us for removing in struct page.
- MD pull request from Song
- Don't schedule block workers on isolated CPUs
* tag 'for-6.10/block-20240511' of git://git.kernel.dk/linux: (84 commits)
blk-throttle: delay initialization until configuration
blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW
block: fix that util can be greater than 100%
block: support to account io_ticks precisely
block: add plug while submitting IO
bcache: fix variable length array abuse in btree_iter
bcache: Remove usage of the deprecated ida_simple_xx() API
md: Revert "md: Fix overflow in is_mddev_idle"
blk-lib: check for kill signal in ioctl BLKDISCARD
block: add a bio_await_chain helper
block: add a blk_alloc_discard_bio helper
block: add a bio_chain_and_submit helper
block: move discard checks into the ioctl handler
block: remove the discard_granularity check in __blkdev_issue_discard
block/ioctl: prefer different overflow check
null_blk: Fix the WARNING: modpost: missing MODULE_DESCRIPTION()
block: fix and simplify blkdevparts= cmdline parsing
block: refine the EOF check in blkdev_iomap_begin
block: add a partscan sysfs attribute for disks
block: add a disk_has_partscan helper
...
Other cgroup policy like bfq, iocost are lazy-initialized when they are
configured for the first time for the device, but blk-throttle is
initialized unconditionally from blkcg_init_disk().
Delay initialization of blk-throttle as well, to save some cpu and
memory overhead if it's not configured.
Noted that once it's initialized, it can't be destroyed until disk
removal, even if it's disabled.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240509121107.3195568-3-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Multiple gendisk instances can allocated/added for single request queue
in case of disk rebind. blkg may still stay in q->blkg_list when calling
blkcg_init_disk() for rebind, then q->blkg_list becomes corrupted.
Fix the list corruption issue by:
- add blkg_init_queue() to initialize q->blkg_list & q->blkcg_mutex only
- move calling blkg_init_queue() into blk_alloc_queue()
The list corruption should be started since commit f1c006f1c6 ("blk-cgroup:
synchronize pd_free_fn() from blkg_free_workfn() and blkcg_deactivate_policy()")
which delays removing blkg from q->blkg_list into blkg_free_workfn().
Fixes: f1c006f1c6 ("blk-cgroup: synchronize pd_free_fn() from blkg_free_workfn() and blkcg_deactivate_policy()")
Fixes: 1059699f87 ("block: move blkcg initialization/destroy into disk allocation/release handler")
Cc: Yu Kuai <yukuai3@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240407125910.4053377-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Use bio_list_merge_init instead of open coding bio_list_merge and
bio_list_init.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Link: https://lore.kernel.org/r/20240328084147.2954434-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Convert any user of ktime_get_ns() to use blk_time_get_ns(), and
ktime_get() to blk_time_get(), so we have a unified API for querying the
current time in nanoseconds or as ktime.
No functional changes intended, this patch just wraps ktime_get_ns()
and ktime_get() with a block helper.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit 99e6038743
("blk-cgroup: pass a gendisk to the blkg allocation helpers") changed
blkg_alloc() to take a struct gendisk instead of a struct request_queue,
but the documentation comment still referred to q.
So, update that comment to refer to disk instead and fix a typo.
Signed-off-by: Nicky Chorley <ndchorley@gmail.com>
Link: https://lore.kernel.org/r/20240114191056.6992-1-ndchorley@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Commit f1c006f1c6 moved deletion of the list blkg->q_node from
blkg_destroy() to blkg_free_workfn(). Switch to using the list
iterators, as we don't need removal protection anymore.
Signed-off-by: Daniel Vacek <neelx@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20240104180031.148148-1-neelx@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Even if BLK_CGROUP is enabled, it does not work for passthrough io.
So skip setting up blkg for passthrough bio.
Reduced processing gives ~5% hike in peak-performance workload.
Signed-off-by: Kundan Kumar <kundan.kumar@samsung.com>
Signed-off-by: Kanchan Joshi <joshi.k@samsung.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20231218152722.1768-1-joshi.k@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blkcg_deactivate_policy() can be called after blkg_destroy_all()
returns, and it isn't necessary since blkg_destroy_all has covered
policy deactivation.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20231117023527.3188627-4-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
"Pretty quiet round for this release. This contains:
- Add support for zoned storage to ublk (Andreas, Ming)
- Series improving performance for drivers that mark themselves as
needing a blocking context for issue (Bart)
- Cleanup the flush logic (Chengming)
- sed opal keyring support (Greg)
- Fixes and improvements to the integrity support (Jinyoung)
- Add some exports for bcachefs that we can hopefully delete again in
the future (Kent)
- deadline throttling fix (Zhiguo)
- Series allowing building the kernel without buffer_head support
(Christoph)
- Sanitize the bio page adding flow (Christoph)
- Write back cache fixes (Christoph)
- MD updates via Song:
- Fix perf regression for raid0 large sequential writes (Jan)
- Fix split bio iostat for raid0 (David)
- Various raid1 fixes (Heinz, Xueshi)
- raid6test build fixes (WANG)
- Deprecate bitmap file support (Christoph)
- Fix deadlock with md sync thread (Yu)
- Refactor md io accounting (Yu)
- Various non-urgent fixes (Li, Yu, Jack)
- Various fixes and cleanups (Arnd, Azeem, Chengming, Damien, Li,
Ming, Nitesh, Ruan, Tejun, Thomas, Xu)"
* tag 'for-6.6/block-2023-08-28' of git://git.kernel.dk/linux: (113 commits)
block: use strscpy() to instead of strncpy()
block: sed-opal: keyring support for SED keys
block: sed-opal: Implement IOC_OPAL_REVERT_LSP
block: sed-opal: Implement IOC_OPAL_DISCOVERY
blk-mq: prealloc tags when increase tagset nr_hw_queues
blk-mq: delete redundant tagset map update when fallback
blk-mq: fix tags leak when shrink nr_hw_queues
ublk: zoned: support REQ_OP_ZONE_RESET_ALL
md: raid0: account for split bio in iostat accounting
md/raid0: Fix performance regression for large sequential writes
md/raid0: Factor out helper for mapping and submitting a bio
md raid1: allow writebehind to work on any leg device set WriteMostly
md/raid1: hold the barrier until handle_read_error() finishes
md/raid1: free the r1bio before waiting for blocked rdev
md/raid1: call free_r1bio() before allow_barrier() in raid_end_bio_io()
blk-cgroup: Fix NULL deref caused by blkg_policy_data being installed before init
drivers/rnbd: restore sysfs interface to rnbd-client
md/raid5-cache: fix null-ptr-deref for r5l_flush_stripe_to_raid()
raid6: test: only check for Altivec if building on powerpc hosts
raid6: test: make sure all intermediate and artifact files are .gitignored
...
When blkg is removed from q->blkg_list from blkg_free_workfn(), queue_lock
has to be held, otherwise, all kinds of bugs(list corruption, hard lockup,
..) can be triggered from blkg_destroy_all().
Fixes: f1c006f1c6 ("blk-cgroup: synchronize pd_free_fn() from blkg_free_workfn() and blkcg_deactivate_policy()")
Cc: Yu Kuai <yukuai3@huawei.com>
Cc: xiaoli feng <xifeng@redhat.com>
Cc: Chunyu Hu <chuhu@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230817141751.1128970-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
blk-iocost sometimes causes the following crash:
BUG: kernel NULL pointer dereference, address: 00000000000000e0
...
RIP: 0010:_raw_spin_lock+0x17/0x30
Code: be 01 02 00 00 e8 79 38 39 ff 31 d2 89 d0 5d c3 0f 1f 00 0f 1f 44 00 00 55 48 89 e5 65 ff 05 48 d0 34 7e b9 01 00 00 00 31 c0 <f0> 0f b1 0f 75 02 5d c3 89 c6 e8 ea 04 00 00 5d c3 0f 1f 84 00 00
RSP: 0018:ffffc900023b3d40 EFLAGS: 00010046
RAX: 0000000000000000 RBX: 00000000000000e0 RCX: 0000000000000001
RDX: ffffc900023b3d20 RSI: ffffc900023b3cf0 RDI: 00000000000000e0
RBP: ffffc900023b3d40 R08: ffffc900023b3c10 R09: 0000000000000003
R10: 0000000000000064 R11: 000000000000000a R12: ffff888102337000
R13: fffffffffffffff2 R14: ffff88810af408c8 R15: ffff8881070c3600
FS: 00007faaaf364fc0(0000) GS:ffff88842fdc0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000e0 CR3: 00000001097b1000 CR4: 0000000000350ea0
Call Trace:
<TASK>
ioc_weight_write+0x13d/0x410
cgroup_file_write+0x7a/0x130
kernfs_fop_write_iter+0xf5/0x170
vfs_write+0x298/0x370
ksys_write+0x5f/0xb0
__x64_sys_write+0x1b/0x20
do_syscall_64+0x3d/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
This happens because iocg->ioc is NULL. The field is initialized by
ioc_pd_init() and never cleared. The NULL deref is caused by
blkcg_activate_policy() installing blkg_policy_data before initializing it.
blkcg_activate_policy() was doing the following:
1. Allocate pd's for all existing blkg's and install them in blkg->pd[].
2. Initialize all pd's.
3. Online all pd's.
blkcg_activate_policy() only grabs the queue_lock and may release and
re-acquire the lock as allocation may need to sleep. ioc_weight_write()
grabs blkcg->lock and iterates all its blkg's. The two can race and if
ioc_weight_write() runs during #1 or between #1 and #2, it can encounter a
pd which is not initialized yet, leading to crash.
The crash can be reproduced with the following script:
#!/bin/bash
echo +io > /sys/fs/cgroup/cgroup.subtree_control
systemd-run --unit touch-sda --scope dd if=/dev/sda of=/dev/null bs=1M count=1 iflag=direct
echo 100 > /sys/fs/cgroup/system.slice/io.weight
bash -c "echo '8:0 enable=1' > /sys/fs/cgroup/io.cost.qos" &
sleep .2
echo 100 > /sys/fs/cgroup/system.slice/io.weight
with the following patch applied:
> diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> index fc49be622e05..38d671d5e10c 100644
> --- a/block/blk-cgroup.c
> +++ b/block/blk-cgroup.c
> @@ -1553,6 +1553,12 @@ int blkcg_activate_policy(struct gendisk *disk, const struct blkcg_policy *pol)
> pd->online = false;
> }
>
> + if (system_state == SYSTEM_RUNNING) {
> + spin_unlock_irq(&q->queue_lock);
> + ssleep(1);
> + spin_lock_irq(&q->queue_lock);
> + }
> +
> /* all allocated, init in the same order */
> if (pol->pd_init_fn)
> list_for_each_entry_reverse(blkg, &q->blkg_list, q_node)
I don't see a reason why all pd's should be allocated, initialized and
onlined together. The only ordering requirement is that parent blkgs to be
initialized and onlined before children, which is guaranteed from the
walking order. Let's fix the bug by allocating, initializing and onlining pd
for each blkg and holding blkcg->lock over initialization and onlining. This
ensures that an installed blkg is always fully initialized and onlined
removing the the race window.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Breno Leitao <leitao@debian.org>
Fixes: 9d179b8654 ("blkcg: Fix multiple bugs in blkcg_activate_policy()")
Link: https://lore.kernel.org/r/ZN0p5_W-Q9mAHBVY@slm.duckdns.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
* for-6.5/block-late:
blk-sysfs: add a new attr_group for blk_mq
blk-iocost: move wbt_enable/disable_default() out of spinlock
blk-wbt: cleanup rwb_enabled() and wbt_disabled()
blk-wbt: remove dead code to handle wbt enable/disable with io inflight
blk-wbt: don't create wbt sysfs entry if CONFIG_BLK_WBT is disabled
blk-mq: fix two misuses on RQF_USE_SCHED
blk-throttle: Fix io statistics for cgroup v1
bcache: Fix bcache device claiming
bcache: Alloc holder object before async registration
raid10: avoid spin_lock from fastpath from raid10_unplug()
md: fix 'delete_mutex' deadlock
md: use mddev->external to select holder in export_rdev()
md/raid1-10: fix casting from randomized structure in raid1_submit_write()
md/raid10: fix the condition to call bio_end_io_acct()
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Merge tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- NVMe pull request via Keith:
- Various cleanups all around (Irvin, Chaitanya, Christophe)
- Better struct packing (Christophe JAILLET)
- Reduce controller error logs for optional commands (Keith)
- Support for >=64KiB block sizes (Daniel Gomez)
- Fabrics fixes and code organization (Max, Chaitanya, Daniel
Wagner)
- bcache updates via Coly:
- Fix a race at init time (Mingzhe Zou)
- Misc fixes and cleanups (Andrea, Thomas, Zheng, Ye)
- use page pinning in the block layer for dio (David)
- convert old block dio code to page pinning (David, Christoph)
- cleanups for pktcdvd (Andy)
- cleanups for rnbd (Guoqing)
- use the unchecked __bio_add_page() for the initial single page
additions (Johannes)
- fix overflows in the Amiga partition handling code (Michael)
- improve mq-deadline zoned device support (Bart)
- keep passthrough requests out of the IO schedulers (Christoph, Ming)
- improve support for flush requests, making them less special to deal
with (Christoph)
- add bdev holder ops and shutdown methods (Christoph)
- fix the name_to_dev_t() situation and use cases (Christoph)
- decouple the block open flags from fmode_t (Christoph)
- ublk updates and cleanups, including adding user copy support (Ming)
- BFQ sanity checking (Bart)
- convert brd from radix to xarray (Pankaj)
- constify various structures (Thomas, Ivan)
- more fine grained persistent reservation ioctl capability checks
(Jingbo)
- misc fixes and cleanups (Arnd, Azeem, Demi, Ed, Hengqi, Hou, Jan,
Jordy, Li, Min, Yu, Zhong, Waiman)
* tag 'for-6.5/block-2023-06-23' of git://git.kernel.dk/linux: (266 commits)
scsi/sg: don't grab scsi host module reference
ext4: Fix warning in blkdev_put()
block: don't return -EINVAL for not found names in devt_from_devname
cdrom: Fix spectre-v1 gadget
block: Improve kernel-doc headers
blk-mq: don't insert passthrough request into sw queue
bsg: make bsg_class a static const structure
ublk: make ublk_chr_class a static const structure
aoe: make aoe_class a static const structure
block/rnbd: make all 'class' structures const
block: fix the exclusive open mask in disk_scan_partitions
block: add overflow checks for Amiga partition support
block: change all __u32 annotations to __be32 in affs_hardblocks.h
block: fix signed int overflow in Amiga partition support
block: add capacity validation in bdev_add_partition()
block: fine-granular CAP_SYS_ADMIN for Persistent Reservation
block: disallow Persistent Reservation on partitions
reiserfs: fix blkdev_put() warning from release_journal_dev()
block: fix wrong mode for blkdev_get_by_dev() from disk_scan_partitions()
block: document the holder argument to blkdev_get_by_path
...
After commit f382fb0bce ("block: remove legacy IO schedulers"),
blkio.throttle.io_serviced and blkio.throttle.io_service_bytes become
the only stable io stats interface of cgroup v1, and these statistics
are done in the blk-throttle code. But the current code only counts the
bios that are actually throttled. When the user does not add the throttle
limit, the io stats for cgroup v1 has nothing. I fix it according to the
statistical method of v2, and made it count all ios accurately.
Fixes: a7b36ee6ba ("block: move blk-throtl fast path inline")
Tested-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Jinke Han <hanjinke.666@bytedance.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230507170631.89607-1-hanjinke.666@bytedance.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When __blkcg_rstat_flush() is called from cgroup_rstat_flush*() code
path, interrupt is always disabled.
When we start to flush blkcg per-cpu stats list in __blkg_release()
for avoiding to leak blkcg_gq's reference in commit 20cb1c2fb7
("blk-cgroup: Flush stats before releasing blkcg_gq"), local irq
isn't disabled yet, then lockdep warning may be triggered because
the dependent cgroup locks may be acquired from irq(soft irq) handler.
Fix the issue by disabling local irq always.
Fixes: 20cb1c2fb7 ("blk-cgroup: Flush stats before releasing blkcg_gq")
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Closes: https://lore.kernel.org/linux-block/pz2wzwnmn5tk3pwpskmjhli6g3qly7eoknilb26of376c7kwxy@qydzpvt6zpis/T/#u
Cc: stable@vger.kernel.org
Cc: Jay Shin <jaeshin@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/20230622084249.1208005-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
As noted by Michal, the blkg_iostat_set's in the lockless list hold
reference to blkg's to protect against their removal. Those blkg's
hold reference to blkcg. When a cgroup is being destroyed,
cgroup_rstat_flush() is only called at css_release_work_fn() which
is called when the blkcg reference count reaches 0. This circular
dependency will prevent blkcg and some blkgs from being freed after
they are made offline.
It is less a problem if the cgroup to be destroyed also has other
controllers like memory that will call cgroup_rstat_flush() which will
clean up the reference count. If block is the only controller that uses
rstat, these offline blkcg and blkgs may never be freed leaking more
and more memory over time.
To prevent this potential memory leak:
- flush blkcg per-cpu stats list in __blkg_release(), when no new stat
can be added
- add global blkg_stat_lock for covering concurrent parent blkg stat
update
- don't grab bio->bi_blkg reference when adding the stats into blkcg's
per-cpu stat list since all stats are guaranteed to be consumed before
releasing blkg instance, and grabbing blkg reference for stats was the
most fragile part of original patch
Based on Waiman's patch:
https://lore.kernel.org/linux-block/20221215033132.230023-3-longman@redhat.com/
Fixes: 3b8cc62987 ("blk-cgroup: Optimize blkcg_rstat_flush()")
Cc: stable@vger.kernel.org
Reported-by: Jay Shin <jaeshin@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: mkoutny@suse.com
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230609234249.1412858-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
When blkg_alloc() is called to allocate a blkcg_gq structure
with the associated blkg_iostat_set's, there are 2 fields within
blkg_iostat_set that requires proper initialization - blkg & sync.
The former field was introduced by commit 3b8cc62987 ("blk-cgroup:
Optimize blkcg_rstat_flush()") while the later one was introduced by
commit f733164829 ("blk-cgroup: reimplement basic IO stats using
cgroup rstat").
Unfortunately those fields in the blkg_iostat_set's are not properly
re-initialized when they are cleared in v1's blkcg_reset_stats(). This
can lead to a kernel panic due to NULL pointer access of the blkg
pointer. The missing initialization of sync is less problematic and
can be a problem in a debug kernel due to missing lockdep initialization.
Fix these problems by re-initializing them after memory clearing.
Fixes: 3b8cc62987 ("blk-cgroup: Optimize blkcg_rstat_flush()")
Fixes: f733164829 ("blk-cgroup: reimplement basic IO stats using cgroup rstat")
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230606180724.2455066-1-longman@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
commit 50e34d7881 ("block: disable the elevator int del_gendisk")
move rq_qos_exit() from disk_release() to del_gendisk(), this will
introduce some problems:
1) If rq_qos_add() is triggered by enabling iocost/iolatency through
cgroupfs, then it can concurrent with del_gendisk(), it's not safe to
write 'q->rq_qos' concurrently.
2) Activate cgroup policy that is relied on rq_qos will call
rq_qos_add() and blkcg_activate_policy(), and if rq_qos_exit() is
called in the middle, null-ptr-dereference will be triggered in
blkcg_activate_policy().
3) blkg_conf_open_bdev() can call blkdev_get_no_open() first to find the
disk, then if rq_qos_exit() from del_gendisk() is done before
rq_qos_add(), then memory will be leaked.
This patch add a new disk level mutex 'rq_qos_mutex':
1) The lock will protect rq_qos_exit() directly.
2) For wbt that doesn't relied on blk-cgroup, rq_qos_add() can only be
called from disk initialization for now because wbt can't be
destructed until rq_qos_exit(), so it's safe not to protect wbt for
now. Hoever, in case that rq_qos dynamically destruction is supported
in the furture, this patch also protect rq_qos_add() from wbt_init()
directly, this is enough because blk-sysfs already synchronize
writers with disk removal.
3) For iocost and iolatency, in order to synchronize disk removal and
cgroup configuration, the lock is held after blkdev_get_no_open()
from blkg_conf_open_bdev(), and is released in blkg_conf_exit().
In order to fix the above memory leak, disk_live() is checked after
holding the new lock.
Fixes: 50e34d7881 ("block: disable the elevator int del_gendisk")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230414084008.2085155-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-6.4/block-2023-05-06' of git://git.kernel.dk/linux
Pull more block updates from Jens Axboe:
- MD pull request via Song:
- Improve raid5 sequential IO performance on spinning disks, which
fixes a regression since v6.0 (Jan Kara)
- Fix bitmap offset types, which fixes an issue introduced in this
merge window (Jonathan Derrick)
- Cleanup of hweight type used for cgroup writeback (Maxim)
- Fix a regression with the "has_submit_bio" changes across partitions
(Ming)
- Cleanup of QUEUE_FLAG_ADD_RANDOM clearing.
We used to set this flag on queues non blk-mq queues, and hence some
drivers clear it unconditionally. Since all of these have since been
converted to true blk-mq drivers, drop the useless clear as the bit
is not set (Chaitanya)
- Fix the flags being set in a bio for a flush for drbd (Christoph)
- Cleanup and deduplication of the code handling setting block device
capacity (Damien)
- Fix for ublk handling IO timeouts (Ming)
- Fix for a regression in blk-cgroup teardown (Tao)
- NBD documentation and code fixes (Eric)
- Convert blk-integrity to using device_attributes rather than a second
kobject to manage lifetimes (Thomas)
* tag 'for-6.4/block-2023-05-06' of git://git.kernel.dk/linux:
ublk: add timeout handler
drbd: correctly submit flush bio on barrier
mailmap: add mailmap entries for Jens Axboe
block: Skip destroyed blkg when restart in blkg_destroy_all()
writeback: fix call of incorrect macro
md: Fix bitmap offset type in sb writer
md/raid5: Improve performance for sequential IO
docs nbd: userspace NBD now favors github over sourceforge
block nbd: use req.cookie instead of req.handle
uapi nbd: add cookie alias to handle
uapi nbd: improve doc links to userspace spec
blk-integrity: register sysfs attributes on struct device
blk-integrity: convert to struct device_attribute
blk-integrity: use sysfs_emit
block/drivers: remove dead clear of random flag
block: sync part's ->bd_has_submit_bio with disk's
block: Cleanup set_capacity()/bdev_set_nr_sectors()
Kernel hang in blkg_destroy_all() when total blkg greater than
BLKG_DESTROY_BATCH_SIZE, because of not removing destroyed blkg in
blkg_list. So the size of blkg_list is same after destroying a
batch of blkg, and the infinite 'restart' occurs.
Since blkg should stay on the queue list until blkg_free_workfn(),
skip destroyed blkg when restart a new round, which will solve this
kernel hang issue and satisfy the previous will to restart.
Reported-by: Xiangfei Ma <xiangfeix.ma@intel.com>
Tested-by: Xiangfei Ma <xiangfeix.ma@intel.com>
Tested-by: Farrah Chen <farrah.chen@intel.com>
Signed-off-by: Tao Su <tao1.su@linux.intel.com>
Fixes: f1c006f1c6 ("blk-cgroup: synchronize pd_free_fn() from blkg_free_workfn() and blkcg_deactivate_policy()")
Suggested-and-reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20230428045149.1310073-1-tao1.su@linux.intel.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'for-6.4/block-2023-04-21' of git://git.kernel.dk/linux
Pull block updates from Jens Axboe:
- drbd patches, bringing us closer to unifying the out-of-tree version
and the in tree one (Andreas, Christoph)
- support for auto-quiesce for the s390 dasd driver (Stefan)
- MD pull request via Song:
- md/bitmap: Optimal last page size (Jon Derrick)
- Various raid10 fixes (Yu Kuai, Li Nan)
- md: add error_handlers for raid0 and linear (Mariusz Tkaczyk)
- NVMe pull request via Christoph:
- Drop redundant pci_enable_pcie_error_reporting (Bjorn Helgaas)
- Validate nvmet module parameters (Chaitanya Kulkarni)
- Fence TCP socket on receive error (Chris Leech)
- Fix async event trace event (Keith Busch)
- Minor cleanups (Chaitanya Kulkarni, zhenwei pi)
- Fix and cleanup nvmet Identify handling (Damien Le Moal,
Christoph Hellwig)
- Fix double blk_mq_complete_request race in the timeout handler
(Lei Yin)
- Fix irq locking in nvme-fcloop (Ming Lei)
- Remove queue mapping helper for rdma devices (Sagi Grimberg)
- use structured request attribute checks for nbd (Jakub)
- fix blk-crypto race conditions between keyslot management (Eric)
- add sed-opal support for reading read locking range attributes
(Ondrej)
- make fault injection configurable for null_blk (Akinobu)
- clean up the request insertion API (Christoph)
- clean up the queue running API (Christoph)
- blkg config helper cleanups (Tejun)
- lazy init support for blk-iolatency (Tejun)
- various fixes and tweaks to ublk (Ming)
- remove hybrid polling. It hasn't really been useful since we got
async polled IO support, and these days we don't support sync polled
IO at all (Keith)
- misc fixes, cleanups, improvements (Zhong, Ondrej, Colin, Chengming,
Chaitanya, me)
* tag 'for-6.4/block-2023-04-21' of git://git.kernel.dk/linux: (118 commits)
nbd: fix incomplete validation of ioctl arg
ublk: don't return 0 in case of any failure
sed-opal: geometry feature reporting command
null_blk: Always check queue mode setting from configfs
block: ublk: switch to ioctl command encoding
blk-mq: fix the blk_mq_add_to_requeue_list call in blk_kick_flush
block, bfq: Fix division by zero error on zero wsum
fault-inject: fix build error when FAULT_INJECTION_CONFIGFS=y and CONFIGFS_FS=m
block: store bdev->bd_disk->fops->submit_bio state in bdev
block: re-arrange the struct block_device fields for better layout
md/raid5: remove unused working_disks variable
md/raid10: don't call bio_start_io_acct twice for bio which experienced read error
md/raid10: fix memleak of md thread
md/raid10: fix memleak for 'conf->bio_split'
md/raid10: fix leak of 'r10bio->remaining' for recovery
md/raid10: don't BUG_ON() in raise_barrier()
md: fix soft lockup in status_resync
md: add error_handlers for raid0 and linear
md: Use optimal I/O size for last bitmap page
md: Fix types in sb writer
...
Guard all the code to punt bios to a per-cgroup submission helper by a
new CONFIG_BLK_CGROUP_PUNT_BIO symbol that is selected by btrfs.
This way non-btrfs kernel builds don't need to have this code.
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
async_bio_lock is only taken from bio submission and workqueue context,
both are never in bottom halves.
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David Sterba <dsterba@suse.com>
REQ_CGROUP_PUNT is a bit annoying as it is hard to follow and adds
a branch to the bio submission hot path. To fix this, export
blkcg_punt_bio_submit and let btrfs call it directly. Add a new
REQ_FS_PRIVATE flag for btrfs to indicate to it's own low-level
bio submission code that a punt to the cgroup submission helper
is required.
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Other rq_qos policies such as wbt and iocost are lazy-initialized when they
are configured for the first time for the device but iolatency is
initialized unconditionally from blkcg_init_disk() during gendisk init. Lazy
init is beneficial because rq_qos policies add runtime overhead when
initialized as every IO has to walk all registered rq_qos callbacks.
This patch switches iolatency to lazy initialization too so that it only
registered its rq_qos policy when it is first configured.
Note that there is a known race condition between blkcg config file writes
and del_gendisk() and this patch makes iolatency susceptible to it by
exposing the init path to race against the deletion path. However, that
problem already exists in iocost and is being worked on.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20230413000649.115785-5-tj@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
We want to support lazy init of rq-qos policies so that iolatency is enabled
lazily on configuration instead of gendisk initialization. The way blkg
config helpers are structured now is a bit awkward for that. Let's
restructure:
* blkcg_conf_open_bdev() is renamed to blkg_conf_open_bdev(). The blkcg_
prefix was used because the bdev opening step is blkg-independent.
However, the distinction is too subtle and confuses more than helps. Let's
switch to blkg prefix so that it's consistent with the type and other
helper names.
* struct blkg_conf_ctx now remembers the original input string and is always
initialized by the new blkg_conf_init().
* blkg_conf_open_bdev() is updated to take a pointer to blkg_conf_ctx like
blkg_conf_prep() and can be called multiple times safely. Instead of
modifying the double pointer to input string directly,
blkg_conf_open_bdev() now sets blkg_conf_ctx->body.
* blkg_conf_finish() is renamed to blkg_conf_exit() for symmetry and now
must be called on all blkg_conf_ctx's which were initialized with
blkg_conf_init().
Combined, this allows the users to either open the bdev first or do it
altogether with blkg_conf_prep() which will help implementing lazy init of
rq-qos policies.
blkg_conf_init/exit() will also be used implement synchronization against
device removal. This is necessary because iolat / iocost are configured
through cgroupfs instead of one of the files under /sys/block/DEVICE. As
cgroupfs operations aren't synchronized with block layer, the lazy init and
other configuration operations may race against device removal. This patch
makes blkg_conf_init/exit() used consistently for all cgroup-orginating
configurations making them a good place to implement explicit
synchronization.
Users are updated accordingly. No behavior change is intended by this patch.
v2: bfq wasn't updated in v1 causing a build error. Fixed.
v3: Update the description to include future use of blkg_conf_init/exit() as
synchronization points.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Yu Kuai <yukuai1@huaweicloud.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230413000649.115785-3-tj@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Now that all RCU flavors have been combined either holding a spin lock,
disabling irq or disabling preemption implies RCU read lock, so there's no
need to use rcu_read_[un]lock() explicitly while holding queue_lock. This
shouldn't cause any behavior changes.
v2: Description updated. Leave __acquires/release on queue_lock alone.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230413000649.115785-2-tj@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
