X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=kernel%2Fcgroup.c;h=03a1b3f754d6aa3fc3be4aa3226beda3973bc3f6;hb=d464c9367c8233be1219e0945ad9f8d567cb3eb7;hp=b5946676f84ef0013f07bcce35b10534dd23de04;hpb=cd5367ae02a488450b714a5d5f47afb014ea6541;p=firefly-linux-kernel-4.4.55.git

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index b5946676f84e..03a1b3f754d6 100644
--- 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 */