Commit 15faafc6 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

sched,init: Fix DEBUG_PREEMPT vs early boot 



Extend 8fb12156 ("init: Pin init task to the boot CPU, initially")
to cover the new PF_NO_SETAFFINITY requirement.

While there, move wait_for_completion(&kthreadd_done) into kernel_init()
to make it absolutely clear it is the very first thing done by the init
thread.

Fixes: 570a752b ("lib/smp_processor_id: Use is_percpu_thread() instead of nr_cpus_allowed")
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarValentin Schneider <valentin.schneider@arm.com>
Tested-by: default avatarValentin Schneider <valentin.schneider@arm.com>
Tested-by: default avatarBorislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/YLS4mbKUrA3Gnb4t@hirez.programming.kicks-ass.net
parent 7b419f47

init/main.c

+6 −5
Original line number Diff line number Diff line
@@ -692,6 +692,7 @@ noinline void __ref rest_init(void) 
	 */

	rcu_read_lock();

	tsk = find_task_by_pid_ns(pid, &init_pid_ns);

	tsk->flags |= PF_NO_SETAFFINITY;

	set_cpus_allowed_ptr(tsk, cpumask_of(smp_processor_id()));

	rcu_read_unlock();
@@ -1440,6 +1441,11 @@ static int __ref kernel_init(void *unused) 
{

	int ret;



	/*

	 * Wait until kthreadd is all set-up.

	 */

	wait_for_completion(&kthreadd_done);



	kernel_init_freeable();

	/* need to finish all async __init code before freeing the memory */

	async_synchronize_full();
@@ -1520,11 +1526,6 @@ void __init console_on_rootfs(void) 


static noinline void __init kernel_init_freeable(void)

{

	/*

	 * Wait until kthreadd is all set-up.

	 */

	wait_for_completion(&kthreadd_done);



	/* Now the scheduler is fully set up and can do blocking allocations */

	gfp_allowed_mask = __GFP_BITS_MASK;

kernel/sched/core.c

+1 −0
Original line number Diff line number Diff line
@@ -8862,6 +8862,7 @@ void __init sched_init_smp(void) 
	/* Move init over to a non-isolated CPU */

	if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0)

		BUG();

	current->flags &= ~PF_NO_SETAFFINITY;

	sched_init_granularity();



	init_sched_rt_class();