The patch titled
cgroups: remove events before destroying subsystem state objects
has been added to the -mm tree. Its filename is
cgroups-remove-events-before-destroying-subsystem-state-objects.patch
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------------------------------------------------------
Subject: cgroups: remove events before destroying subsystem state objects
From: "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx>
Events should be removed after rmdir of cgroup directory, but before
destroying subsystem state objects. Let's take reference to cgroup
directory dentry to do that.
Signed-off-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hioryu@xxxxxxxxxxxxxx>
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: Li Zefan <lizf@xxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxx>
Cc: Dan Malek <dan@xxxxxxxxxxxxxxxxx>
Cc: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/cgroup.h | 3 ---
kernel/cgroup.c | 8 ++++++++
mm/memcontrol.c | 9 ---------
3 files changed, 8 insertions(+), 12 deletions(-)
diff -puN include/linux/cgroup.h~cgroups-remove-events-before-destroying-subsystem-state-objects include/linux/cgroup.h
--- a/include/linux/cgroup.h~cgroups-remove-events-before-destroying-subsystem-state-objects
+++ a/include/linux/cgroup.h
@@ -395,9 +395,6 @@ struct cftype {
* closes the eventfd or on cgroup removing.
* This callback must be implemented, if you want provide
* notification functionality.
- *
- * Be careful. It can be called after destroy(), so you have
- * to keep all nesessary data, until all events are removed.
*/
int (*unregister_event)(struct cgroup *cgrp, struct cftype *cft,
struct eventfd_ctx *eventfd);
diff -puN kernel/cgroup.c~cgroups-remove-events-before-destroying-subsystem-state-objects kernel/cgroup.c
--- a/kernel/cgroup.c~cgroups-remove-events-before-destroying-subsystem-state-objects
+++ a/kernel/cgroup.c
@@ -2979,6 +2979,7 @@ static void cgroup_event_remove(struct w
eventfd_ctx_put(event->eventfd);
kfree(event);
+ dput(cgrp->dentry);
}
/*
@@ -3099,6 +3100,13 @@ static int cgroup_write_event_control(st
goto fail;
}
+ /*
+ * Events should be removed after rmdir of cgroup directory, but before
+ * destroying subsystem state objects. Let's take reference to cgroup
+ * directory dentry to do that.
+ */
+ dget(cgrp->dentry);
+
spin_lock(&cgrp->event_list_lock);
list_add(&event->list, &cgrp->event_list);
spin_unlock(&cgrp->event_list_lock);
diff -puN mm/memcontrol.c~cgroups-remove-events-before-destroying-subsystem-state-objects mm/memcontrol.c
--- a/mm/memcontrol.c~cgroups-remove-events-before-destroying-subsystem-state-objects
+++ a/mm/memcontrol.c
@@ -3353,12 +3353,6 @@ static int mem_cgroup_register_event(str
}
}
- /*
- * We need to increment refcnt to be sure that all thresholds
- * will be unregistered before calling __mem_cgroup_free()
- */
- mem_cgroup_get(memcg);
-
if (type == _MEM)
rcu_assign_pointer(memcg->thresholds, thresholds_new);
else
@@ -3452,9 +3446,6 @@ assign:
/* To be sure that nobody uses thresholds before freeing it */
synchronize_rcu();
- for (i = 0; i < thresholds->size - size; i++)
- mem_cgroup_put(memcg);
-
kfree(thresholds);
unlock:
mutex_unlock(&memcg->thresholds_lock);
_
Patches currently in -mm which might be from kirill@xxxxxxxxxxxxx are
cgroups-fix-contents-in-cgroups-documentation.patch
cgroup-implement-eventfd-based-generic-api-for-notifications.patch
cgroup-implement-eventfd-based-generic-api-for-notifications-kconfig-fix.patch
cgroup-implement-eventfd-based-generic-api-for-notifications-fixes.patch
memcg-extract-mem_group_usage-from-mem_cgroup_read.patch
memcg-rework-usage-of-stats-by-soft-limit.patch
memcg-implement-memory-thresholds.patch
memcg-implement-memory-thresholds-checkpatch-fixes.patch
memcg-implement-memory-thresholds-checkpatch-fixes-fix.patch
memcg-implement-memory-thresholds-check-if-first-threshold-crossed.patch
memcg-typo-in-comment-to-mem_cgroup_print_oom_info.patch
memcg-update-threshold-and-softlimit-at-commit-v2.patch
memcg-share-event-counter-rather-than-duplicate-v2.patch
memcg-update-memcg_testtxt.patch
cgroups-fix-race-between-userspace-and-kernelspace.patch
cgroups-remove-events-before-destroying-subsystem-state-objects.patch
cgroups-add-simple-listener-of-cgroup-events-to-documentation.patch
memcg-update-memcg_testtxt-to-describe-memory-thresholds.patch
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