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authorLi Zefan <lizf@cn.fujitsu.com>2009-02-11 13:04:36 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-02-11 14:25:36 -0800
commitcfebe563bd0a3ff97e1bc167123120d59c7a84db (patch)
tree6178bf45bcccaf3d43d87cfe0eef059d849c7140
parent01c4a4283137d24c9cc3785f1f312e895a18f273 (diff)
downloadlinux-stericsson-cfebe563bd0a3ff97e1bc167123120d59c7a84db.tar.gz
cgroups: fix lockdep subclasses overflow
I enabled all cgroup subsystems when compiling kernel, and then: # mount -t cgroup -o net_cls xxx /mnt # mkdir /mnt/0 This showed up immediately: BUG: MAX_LOCKDEP_SUBCLASSES too low! turning off the locking correctness validator. It's caused by the cgroup hierarchy lock: for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (ss->root == root) mutex_lock_nested(&ss->hierarchy_mutex, i); } Now we have 9 cgroup subsystems, and the above 'i' for net_cls is 8, but MAX_LOCKDEP_SUBCLASSES is 8. This patch uses different lockdep keys for different subsystems. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/cgroup.h1
-rw-r--r--kernel/cgroup.c3
2 files changed, 3 insertions, 1 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index e4e8e117d27d..499900d0cee7 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -378,6 +378,7 @@ struct cgroup_subsys {
* - initiating hotplug events
*/
struct mutex hierarchy_mutex;
+ struct lock_class_key subsys_key;
/*
* Link to parent, and list entry in parent's children.
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 5a54ff42874e..e14db9c089b9 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2351,7 +2351,7 @@ static void cgroup_lock_hierarchy(struct cgroupfs_root *root)
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
if (ss->root == root)
- mutex_lock_nested(&ss->hierarchy_mutex, i);
+ mutex_lock(&ss->hierarchy_mutex);
}
}
@@ -2637,6 +2637,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
BUG_ON(!list_empty(&init_task.tasks));
mutex_init(&ss->hierarchy_mutex);
+ lockdep_set_class(&ss->hierarchy_mutex, &ss->subsys_key);
ss->active = 1;
}