3.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zefan Li <lizefan@xxxxxxxxxx> commit 79063bffc81f82689bd90e16da1b49408f3bf095 upstream. When we clear cpuset.cpus, cpuset.effective_cpus won't be cleared: # mount -t cgroup -o cpuset xxx /mnt # mkdir /mnt/tmp # echo 0 > /mnt/tmp/cpuset.cpus # echo > /mnt/tmp/cpuset.cpus # cat cpuset.cpus # cat cpuset.effective_cpus 0-15 And a kernel warning in update_cpumasks_hier() is triggered: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 4028 at kernel/cpuset.c:894 update_cpumasks_hier+0x471/0x650() Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> Tested-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- kernel/cpuset.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -873,7 +873,7 @@ static void update_cpumasks_hier(struct * If it becomes empty, inherit the effective mask of the * parent, which is guaranteed to have some CPUs. */ - if (cpumask_empty(new_cpus)) + if (cgroup_on_dfl(cp->css.cgroup) && cpumask_empty(new_cpus)) cpumask_copy(new_cpus, parent->effective_cpus); /* Skip the whole subtree if the cpumask remains the same. */ @@ -1129,7 +1129,7 @@ static void update_nodemasks_hier(struct * If it becomes empty, inherit the effective mask of the * parent, which is guaranteed to have some MEMs. */ - if (nodes_empty(*new_mems)) + if (cgroup_on_dfl(cp->css.cgroup) && nodes_empty(*new_mems)) *new_mems = parent->effective_mems; /* Skip the whole subtree if the nodemask remains the same. */ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html