| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Mon, 12 Nov 2012 19:01:38 -0800
From: Tejun Heo <tj@...nel.org>
To: lizefan@...wei.com, containers@...ts.linux-foundation.org,
cgroups@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: mhocko@...e.cz, glommer@...allels.com, Tejun Heo <tj@...nel.org>
Subject: [PATCH 11/17] cgroup: separate out cgroup_destroy_locked()
Separate out cgroup_destroy_locked() from cgroup_destroy(). This will
be later used in cgroup_create() failure path.
While at it, add lockdep asserts on i_mutex and cgroup_mutex, and move
@d and @parent assignments to their declarations.
This patch doesn't introduce any functional difference.
Signed-off-by: Tejun Heo <tj@...nel.org>
---
kernel/cgroup.c | 40 +++++++++++++++++++++++++---------------
1 file changed, 25 insertions(+), 15 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index c5368c0..afc47d6 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -242,6 +242,8 @@ static DEFINE_SPINLOCK(hierarchy_id_lock);
*/
static int need_forkexit_callback __read_mostly;
+static int cgroup_destroy_locked(struct cgroup *cgrp);
+
#ifdef CONFIG_PROVE_LOCKING
int cgroup_lock_is_held(void)
{
@@ -4209,22 +4211,20 @@ static int cgroup_has_css_refs(struct cgroup *cgrp)
return 0;
}
-static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
+static int cgroup_destroy_locked(struct cgroup *cgrp)
+ __releases(&cgroup_mutex) __acquires(&cgroup_mutex)
{
- struct cgroup *cgrp = dentry->d_fsdata;
- struct dentry *d;
- struct cgroup *parent;
+ struct dentry *d = cgrp->dentry;
+ struct cgroup *parent = cgrp->parent;
DEFINE_WAIT(wait);
struct cgroup_event *event, *tmp;
struct cgroup_subsys *ss;
- /* the vfs holds both inode->i_mutex already */
- mutex_lock(&cgroup_mutex);
- parent = cgrp->parent;
- if (atomic_read(&cgrp->count) || !list_empty(&cgrp->children)) {
- mutex_unlock(&cgroup_mutex);
+ lockdep_assert_held(&d->d_inode->i_mutex);
+ lockdep_assert_held(&cgroup_mutex);
+
+ if (atomic_read(&cgrp->count) || !list_empty(&cgrp->children))
return -EBUSY;
- }
/*
* Block new css_tryget() by deactivating refcnt and mark @cgrp
@@ -4243,7 +4243,9 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
/*
* Tell subsystems to initate destruction. pre_destroy() should be
* called with cgroup_mutex unlocked. See 3fa59dfbc3 ("cgroup: fix
- * potential deadlock in pre_destroy") for details.
+ * potential deadlock in pre_destroy") for details. This temporary
+ * unlocking should go away once cgroup_mutex is unexported from
+ * controllers.
*/
mutex_unlock(&cgroup_mutex);
for_each_subsys(cgrp->root, ss)
@@ -4268,11 +4270,9 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
/* delete this cgroup from parent->children */
list_del_rcu(&cgrp->sibling);
-
list_del_init(&cgrp->allcg_node);
- d = dget(cgrp->dentry);
-
+ dget(d);
cgroup_d_remove_dir(d);
dput(d);
@@ -4293,10 +4293,20 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
}
spin_unlock(&cgrp->event_list_lock);
- mutex_unlock(&cgroup_mutex);
return 0;
}
+static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry)
+{
+ int ret;
+
+ mutex_lock(&cgroup_mutex);
+ ret = cgroup_destroy_locked(dentry->d_fsdata);
+ mutex_unlock(&cgroup_mutex);
+
+ return ret;
+}
+
static void __init_or_module cgroup_init_cftsets(struct cgroup_subsys *ss)
{
INIT_LIST_HEAD(&ss->cftsets);
--
1.7.11.7
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists