Merge branch 'for-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
"Two patches to fix fallouts from the kernfs conversion:
Li's patch to stop leaking cgroup_root refs across multiple mounts and
the other fixes the 90s hang during shutdown caused by always using
root's uid/gid for new cgroup dirs and files."
* 'for-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: newly created dirs and files should be owned by the creator
cgroup: fix top cgroup refcnt leak
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index fede3d3..9fcdaa7 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1487,6 +1487,7 @@
struct cgroup_sb_opts opts;
struct dentry *dentry;
int ret;
+ bool new_sb;
/*
* The first time anyone tries to mount a cgroup, enable the list
@@ -1603,8 +1604,8 @@
if (ret)
return ERR_PTR(ret);
- dentry = kernfs_mount(fs_type, flags, root->kf_root, NULL);
- if (IS_ERR(dentry))
+ dentry = kernfs_mount(fs_type, flags, root->kf_root, &new_sb);
+ if (IS_ERR(dentry) || !new_sb)
cgroup_put(&root->cgrp);
return dentry;
}
@@ -2345,11 +2346,26 @@
return ret;
}
+/* set uid and gid of cgroup dirs and files to that of the creator */
+static int cgroup_kn_set_ugid(struct kernfs_node *kn)
+{
+ struct iattr iattr = { .ia_valid = ATTR_UID | ATTR_GID,
+ .ia_uid = current_fsuid(),
+ .ia_gid = current_fsgid(), };
+
+ if (uid_eq(iattr.ia_uid, GLOBAL_ROOT_UID) &&
+ gid_eq(iattr.ia_gid, GLOBAL_ROOT_GID))
+ return 0;
+
+ return kernfs_setattr(kn, &iattr);
+}
+
static int cgroup_add_file(struct cgroup *cgrp, struct cftype *cft)
{
char name[CGROUP_FILE_NAME_MAX];
struct kernfs_node *kn;
struct lock_class_key *key = NULL;
+ int ret;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
key = &cft->lockdep_key;
@@ -2357,7 +2373,13 @@
kn = __kernfs_create_file(cgrp->kn, cgroup_file_name(cgrp, cft, name),
cgroup_file_mode(cft), 0, cft->kf_ops, cft,
NULL, false, key);
- return PTR_ERR_OR_ZERO(kn);
+ if (IS_ERR(kn))
+ return PTR_ERR(kn);
+
+ ret = cgroup_kn_set_ugid(kn);
+ if (ret)
+ kernfs_remove(kn);
+ return ret;
}
/**
@@ -3752,6 +3774,10 @@
*/
idr_replace(&root->cgroup_idr, cgrp, cgrp->id);
+ err = cgroup_kn_set_ugid(kn);
+ if (err)
+ goto err_destroy;
+
err = cgroup_addrm_files(cgrp, cgroup_base_files, true);
if (err)
goto err_destroy;
