Merge branch 'linux-linaro-lsk-v4.4' into linux-linaro-lsk-v4.4-android

[firefly-linux-kernel-4.4.55.git] / kernel / cgroup.c

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b5946676f84ef0013f07bcce35b10534dd23de04..03a1b3f754d6aa3fc3be4aa3226beda3973bc3f6 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2686,7 +2686,8 @@ static int cgroup_procs_write_permission(struct task_struct *task,
         */
        if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) &&
            !uid_eq(cred->euid, tcred->uid) &&
-           !uid_eq(cred->euid, tcred->suid))
+           !uid_eq(cred->euid, tcred->suid) &&
+           !ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
                ret = -EACCES;
 
        if (!ret && cgroup_on_dfl(dst_cgrp)) {
@@ -5326,6 +5327,12 @@ int __init cgroup_init(void)
        BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
        BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
 
+       /*
+        * The latency of the synchronize_sched() is too high for cgroups,
+        * avoid it at the cost of forcing all readers into the slow path.
+        */
+       rcu_sync_enter_start(&cgroup_threadgroup_rwsem.rss);
+
        mutex_lock(&cgroup_mutex);
 
        /* Add init_css_set to the hash table */