The patch titled
cgroups: fix lockdep subclasses overflow
has been removed from the -mm tree. Its filename was
cgroups-fix-lockdep-subclasses-overflow.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: cgroups: fix lockdep subclasses overflow
From: Li Zefan <lizf@xxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxx>
Acked-by: Paul Menage <menage@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/cgroup.h | 1 +
kernel/cgroup.c | 3 ++-
2 files changed, 3 insertions(+), 1 deletion(-)
diff -puN include/linux/cgroup.h~cgroups-fix-lockdep-subclasses-overflow include/linux/cgroup.h
--- a/include/linux/cgroup.h~cgroups-fix-lockdep-subclasses-overflow
+++ a/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 -puN kernel/cgroup.c~cgroups-fix-lockdep-subclasses-overflow kernel/cgroup.c
--- a/kernel/cgroup.c~cgroups-fix-lockdep-subclasses-overflow
+++ a/kernel/cgroup.c
@@ -2351,7 +2351,7 @@ static void cgroup_lock_hierarchy(struct
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(st
BUG_ON(!list_empty(&init_task.tasks));
mutex_init(&ss->hierarchy_mutex);
+ lockdep_set_class(&ss->hierarchy_mutex, &ss->subsys_key);
ss->active = 1;
}
_
Patches currently in -mm which might be from lizf@xxxxxxxxxxxxxx are
origin.patch
linux-next.patch
cgroups-fix-possible-use-after-free.patch
vfs-add-missing-unlock-in-sget.patch
relax-ns_can_attach-checks-to-allow-attaching-to-grandchild-cgroups.patch
cgroup-css-id-support.patch
cgroup-fix-frequent-ebusy-at-rmdir.patch
memcg-use-css-id.patch
memcg-hierarchical-stat.patch
memcg-fix-shrinking-memory-to-return-ebusy-by-fixing-retry-algorithm.patch
memcg-fix-oom-killer-under-memcg.patch
memcg-fix-oom-killer-under-memcg-fix2.patch
memcg-fix-oom-killer-under-memcg-fix.patch
memcg-show-memcg-information-during-oom.patch
memcg-show-memcg-information-during-oom-fix2.patch
memcg-show-memcg-information-during-oom-fix.patch
memcg-show-memcg-information-during-oom-fix-fix.patch
memcg-show-memcg-information-during-oom-fix-fix-checkpatch-fixes.patch
cpuset-fix-possible-races-in-cpu-memory-hotplug.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
