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-rw-r--r--init/Kconfig1
-rw-r--r--init/main.c27
2 files changed, 23 insertions, 5 deletions
diff --git a/init/Kconfig b/init/Kconfig
index bc4c180c66a5..ee0f03b69d11 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -809,6 +809,7 @@ config CGROUP_HUGETLB
config CPUSETS
bool "Cpuset controller"
+ depends on SMP
help
This option will let you create and manage CPUSETs which
allow dynamically partitioning a system into sets of CPUs and
diff --git a/init/main.c b/init/main.c
index f866510472d7..df58a416dd1d 100644
--- a/init/main.c
+++ b/init/main.c
@@ -389,6 +389,7 @@ static __initdata DECLARE_COMPLETION(kthreadd_done);
static noinline void __ref rest_init(void)
{
+ struct task_struct *tsk;
int pid;
rcu_scheduler_starting();
@@ -397,12 +398,32 @@ static noinline void __ref rest_init(void)
* the init task will end up wanting to create kthreads, which, if
* we schedule it before we create kthreadd, will OOPS.
*/
- kernel_thread(kernel_init, NULL, CLONE_FS);
+ pid = kernel_thread(kernel_init, NULL, CLONE_FS);
+ /*
+ * Pin init on the boot CPU. Task migration is not properly working
+ * until sched_init_smp() has been run. It will set the allowed
+ * CPUs for init to the non isolated CPUs.
+ */
+ rcu_read_lock();
+ tsk = find_task_by_pid_ns(pid, &init_pid_ns);
+ set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));
+ rcu_read_unlock();
+
numa_default_policy();
pid = kernel_thread(kthreadd, NULL, CLONE_FS | CLONE_FILES);
rcu_read_lock();
kthreadd_task = find_task_by_pid_ns(pid, &init_pid_ns);
rcu_read_unlock();
+
+ /*
+ * Enable might_sleep() and smp_processor_id() checks.
+ * They cannot be enabled earlier because with CONFIG_PRREMPT=y
+ * kernel_thread() would trigger might_sleep() splats. With
+ * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
+ * already, but it's stuck on the kthreadd_done completion.
+ */
+ system_state = SYSTEM_SCHEDULING;
+
complete(&kthreadd_done);
/*
@@ -1015,10 +1036,6 @@ static noinline void __init kernel_init_freeable(void)
* init can allocate pages on any node
*/
set_mems_allowed(node_states[N_MEMORY]);
- /*
- * init can run on any cpu.
- */
- set_cpus_allowed_ptr(current, cpu_all_mask);
cad_pid = task_pid(current);