user/sven/linux.git/kernel/cgroup.c, branch v3.10.8

cgroup: fix umount vs cgroup_cfts_commit() race

2013-08-12T01:35:24Z

commit 084457f284abf6789d90509ee11dae383842b23b upstream. cgroup_cfts_commit() uses dget() to keep cgroup alive after cgroup_mutex is dropped, but dget() won't prevent cgroupfs from being umounted. When the race happens, vfs will see some dentries with non-zero refcnt while umount is in process. Keep running this: mount -t cgroup -o blkio xxx /cgroup umount /cgroup And this: modprobe cfq-iosched rmmod cfs-iosched After a while, the BUG() in shrink_dcache_for_umount_subtree() may be triggered: BUG: Dentry xxx{i=0,n=blkio.yyy} still in use (1) [umount of cgroup cgroup] Signed-off-by: Li Zefan Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

cgroup: fix umount vs cgroup_event_remove() race

2013-07-22T01:21:25Z

commit 1c8158eeae0f37d0eee9f1fbe68080df6a408df2 upstream. commit 5db9a4d99b0157a513944e9a44d29c9cec2e91dc Author: Tejun Heo Date: Sat Jul 7 16:08:18 2012 -0700 cgroup: fix cgroup hierarchy umount race This commit fixed a race caused by the dput() in css_dput_fn(), but the dput() in cgroup_event_remove() can also lead to the same BUG(). Signed-off-by: Li Zefan Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman

cgroup: warn about mismatching options of a new mount of an existing hierarchy

2013-05-28T22:59:39Z

With the new __DEVEL__sane_behavior mount option was introduced, if the root cgroup is alive with no xattr function, to mount a new cgroup with xattr will be rejected in terms of design which just fine. However, if the root cgroup does not mounted with __DEVEL__sane_hehavior, to create a new cgroup with xattr option will succeed although after that the EA function does not works as expected but will get ENOTSUPP for setting up attributes under either cgroup. e.g. setfattr: /cgroup2/test: Operation not supported Instead of keeping silence in this case, it's better to drop a log entry in warning level. That would be helpful to understand the reason behind the scene from the user's perspective, and this is essentially an improvement does not break the backward compatibilities. With this fix, above mount attemption will keep up works as usual but the following line cound be found at the system log: [ ...] cgroup: new mount options do not match the existing superblock tj: minor formatting / message updates. Signed-off-by: Jie Liu Reported-by: Alexey Kodanev Signed-off-by: Tejun Heo Cc: stable@vger.kernel.org

cgroup: fix a subtle bug in descendant pre-order walk

2013-05-24T01:50:24Z

When cgroup_next_descendant_pre() initiates a walk, it checks whether the subtree root doesn't have any children and if not returns NULL. Later code assumes that the subtree isn't empty. This is broken because the subtree may become empty inbetween, which can lead to the traversal escaping the subtree by walking to the sibling of the subtree root. There's no reason to have the early exit path. Remove it along with the later assumption that the subtree isn't empty. This simplifies the code a bit and fixes the subtle bug. While at it, fix the comment of cgroup_for_each_descendant_pre() which was incorrectly referring to ->css_offline() instead of ->css_online(). Signed-off-by: Tejun Heo Reviewed-by: Michal Hocko Cc: stable@vger.kernel.org

cgroup: initialize xattr before calling d_instantiate()

2013-05-14T15:24:15Z

cgroup_create_file() calls d_instantiate(), which may decide to look at the xattrs on the file. Smack always does this and SELinux can be configured to do so. But cgroup_add_file() didn't initialize xattrs before calling cgroup_create_file(), which finally leads to dereferencing NULL dentry->d_fsdata. This bug has been there since cgroup xattr was introduced. Cc: # 3.8.x Reported-by: Ivan Bulatovic Reported-by: Casey Schaufler Signed-off-by: Li Zefan Signed-off-by: Tejun Heo

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-05-02T00:51:54Z

Pull VFS updates from Al Viro, Misc cleanups all over the place, mainly wrt /proc interfaces (switch create_proc_entry to proc_create(), get rid of the deprecated create_proc_read_entry() in favor of using proc_create_data() and seq_file etc). 7kloc removed. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits) don't bother with deferred freeing of fdtables proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h proc: Make the PROC_I() and PDE() macros internal to procfs proc: Supply a function to remove a proc entry by PDE take cgroup_open() and cpuset_open() to fs/proc/base.c ppc: Clean up scanlog ppc: Clean up rtas_flash driver somewhat hostap: proc: Use remove_proc_subtree() drm: proc: Use remove_proc_subtree() drm: proc: Use minor->index to label things, not PDE->name drm: Constify drm_proc_list[] zoran: Don't print proc_dir_entry data in debug reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show() proc: Supply an accessor for getting the data from a PDE's parent airo: Use remove_proc_subtree() rtl8192u: Don't need to save device proc dir PDE rtl8187se: Use a dir under /proc/net/r8180/ proc: Add proc_mkdir_data() proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h} proc: Move PDE_NET() to fs/proc/proc_net.c ...

take cgroup_open() and cpuset_open() to fs/proc/base.c

2013-05-01T21:29:46Z

Signed-off-by: Al Viro

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2013-04-30T14:43:28Z

Pull scheduler changes from Ingo Molnar: "The main changes in this development cycle were: - full dynticks preparatory work by Frederic Weisbecker - factor out the cpu time accounting code better, by Li Zefan - multi-CPU load balancer cleanups and improvements by Joonsoo Kim - various smaller fixes and cleanups" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits) sched: Fix init NOHZ_IDLE flag sched: Prevent to re-select dst-cpu in load_balance() sched: Rename load_balance_tmpmask to load_balance_mask sched: Move up affinity check to mitigate useless redoing overhead sched: Don't consider other cpus in our group in case of NEWLY_IDLE sched: Explicitly cpu_idle_type checking in rebalance_domains() sched: Change position of resched_cpu() in load_balance() sched: Fix wrong rq's runnable_avg update with rt tasks sched: Document task_struct::personality field sched/cpuacct/UML: Fix header file dependency bug on the UML build cgroup: Kill subsys.active flag sched/cpuacct: No need to check subsys active state sched/cpuacct: Initialize cpuacct subsystem earlier sched/cpuacct: Initialize root cpuacct earlier sched/cpuacct: Allocate per_cpu cpuusage for root cpuacct statically sched/cpuacct: Clean up cpuacct.h sched/cpuacct: Remove redundant NULL checks in cpuacct_acount_field() sched/cpuacct: Remove redundant NULL checks in cpuacct_charge() sched/cpuacct: Add cpuacct_acount_field() sched/cpuacct: Add cpuacct_init() ...

Merge branch 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2013-04-30T02:14:20Z

Pull cgroup updates from Tejun Heo: - Fixes and a lot of cleanups. Locking cleanup is finally complete. cgroup_mutex is no longer exposed to individual controlelrs which used to cause nasty deadlock issues. Li fixed and cleaned up quite a bit including long standing ones like racy cgroup_path(). - device cgroup now supports proper hierarchy thanks to Aristeu. - perf_event cgroup now supports proper hierarchy. - A new mount option "__DEVEL__sane_behavior" is added. As indicated by the name, this option is to be used for development only at this point and generates a warning message when used. Unfortunately, cgroup interface currently has too many brekages and inconsistencies to implement a consistent and unified hierarchy on top. The new flag is used to collect the behavior changes which are necessary to implement consistent unified hierarchy. It's likely that this flag won't be used verbatim when it becomes ready but will be enabled implicitly along with unified hierarchy. The option currently disables some of broken behaviors in cgroup core and also .use_hierarchy switch in memcg (will be routed through -mm), which can be used to make very unusual hierarchy where nesting is partially honored. It will also be used to implement hierarchy support for blk-throttle which would be impossible otherwise without introducing a full separate set of control knobs. This is essentially versioning of interface which isn't very nice but at this point I can't see any other options which would allow keeping the interface the same while moving towards hierarchy behavior which is at least somewhat sane. The planned unified hierarchy is likely to require some level of adaptation from userland anyway, so I think it'd be best to take the chance and update the interface such that it's supportable in the long term. Maintaining the existing interface does complicate cgroup core but shouldn't put too much strain on individual controllers and I think it'd be manageable for the foreseeable future. Maybe we'll be able to drop it in a decade. Fix up conflicts (including a semantic one adding a new #include to ppc that was uncovered by header the file changes) as per Tejun. * 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (45 commits) cpuset: fix compile warning when CONFIG_SMP=n cpuset: fix cpu hotplug vs rebuild_sched_domains() race cpuset: use rebuild_sched_domains() in cpuset_hotplug_workfn() cgroup: restore the call to eventfd->poll() cgroup: fix use-after-free when umounting cgroupfs cgroup: fix broken file xattrs devcg: remove parent_cgroup. memcg: force use_hierarchy if sane_behavior cgroup: remove cgrp->top_cgroup cgroup: introduce sane_behavior mount option move cgroupfs_root to include/linux/cgroup.h cgroup: convert cgroupfs_root flag bits to masks and add CGRP_ prefix cgroup: make cgroup_path() not print double slashes Revert "cgroup: remove bind() method from cgroup_subsys." perf: make perf_event cgroup hierarchical cgroup: implement cgroup_is_descendant() cgroup: make sure parent won't be destroyed before its children cgroup: remove bind() method from cgroup_subsys. devcg: remove broken_hierarchy tag cgroup: remove cgroup_lock_is_held() ...

Merge branch 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2013-04-30T02:07:40Z

Pull workqueue updates from Tejun Heo: "A lot of activities on workqueue side this time. The changes achieve the followings. - WQ_UNBOUND workqueues - the workqueues which are per-cpu - are updated to be able to interface with multiple backend worker pools. This involved a lot of churning but the end result seems actually neater as unbound workqueues are now a lot closer to per-cpu ones. - The ability to interface with multiple backend worker pools are used to implement unbound workqueues with custom attributes. Currently the supported attributes are the nice level and CPU affinity. It may be expanded to include cgroup association in future. The attributes can be specified either by calling apply_workqueue_attrs() or through /sys/bus/workqueue/WQ_NAME/* if the workqueue in question is exported through sysfs. The backend worker pools are keyed by the actual attributes and shared by any workqueues which share the same attributes. When attributes of a workqueue are changed, the workqueue binds to the worker pool with the specified attributes while leaving the work items which are already executing in its previous worker pools alone. This allows converting custom worker pool implementations which want worker attribute tuning to use workqueues. The writeback pool is already converted in block tree and there are a couple others are likely to follow including btrfs io workers. - WQ_UNBOUND's ability to bind to multiple worker pools is also used to make it NUMA-aware. Because there's no association between work item issuer and the specific worker assigned to execute it, before this change, using unbound workqueue led to unnecessary cross-node bouncing and it couldn't be helped by autonuma as it requires tasks to have implicit node affinity and workers are assigned randomly. After these changes, an unbound workqueue now binds to multiple NUMA-affine worker pools so that queued work items are executed in the same node. This is turned on by default but can be disabled system-wide or for individual workqueues. Crypto was requesting NUMA affinity as encrypting data across different nodes can contribute noticeable overhead and doing it per-cpu was too limiting for certain cases and IO throughput could be bottlenecked by one CPU being fully occupied while others have idle cycles. While the new features required a lot of changes including restructuring locking, it didn't complicate the execution paths much. The unbound workqueue handling is now closer to per-cpu ones and the new features are implemented by simply associating a workqueue with different sets of backend worker pools without changing queue, execution or flush paths. As such, even though the amount of change is very high, I feel relatively safe in that it isn't likely to cause subtle issues with basic correctness of work item execution and handling. If something is wrong, it's likely to show up as being associated with worker pools with the wrong attributes or OOPS while workqueue attributes are being changed or during CPU hotplug. While this creates more backend worker pools, it doesn't add too many more workers unless, of course, there are many workqueues with unique combinations of attributes. Assuming everything else is the same, NUMA awareness costs an extra worker pool per NUMA node with online CPUs. There are also a couple things which are being routed outside the workqueue tree. - block tree pulled in workqueue for-3.10 so that writeback worker pool can be converted to unbound workqueue with sysfs control exposed. This simplifies the code, makes writeback workers NUMA-aware and allows tuning nice level and CPU affinity via sysfs. - The conversion to workqueue means that there's no 1:1 association between a specific worker, which makes writeback folks unhappy as they want to be able to tell which filesystem caused a problem from backtrace on systems with many filesystems mounted. This is resolved by allowing work items to set debug info string which is printed when the task is dumped. As this change involves unifying implementations of dump_stack() and friends in arch codes, it's being routed through Andrew's -mm tree." * 'for-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (84 commits) workqueue: use kmem_cache_free() instead of kfree() workqueue: avoid false negative WARN_ON() in destroy_workqueue() workqueue: update sysfs interface to reflect NUMA awareness and a kernel param to disable NUMA affinity workqueue: implement NUMA affinity for unbound workqueues workqueue: introduce put_pwq_unlocked() workqueue: introduce numa_pwq_tbl_install() workqueue: use NUMA-aware allocation for pool_workqueues workqueue: break init_and_link_pwq() into two functions and introduce alloc_unbound_pwq() workqueue: map an unbound workqueues to multiple per-node pool_workqueues workqueue: move hot fields of workqueue_struct to the end workqueue: make workqueue->name[] fixed len workqueue: add workqueue->unbound_attrs workqueue: determine NUMA node of workers accourding to the allowed cpumask workqueue: drop 'H' from kworker names of unbound worker pools workqueue: add wq_numa_tbl_len and wq_numa_possible_cpumask[] workqueue: move pwq_pool_locking outside of get/put_unbound_pool() workqueue: fix memory leak in apply_workqueue_attrs() workqueue: fix unbound workqueue attrs hashing / comparison workqueue: fix race condition in unbound workqueue free path workqueue: remove pwq_lock which is no longer used ...