Merge tag 'sched_urgent_for_v6.12_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduling fixes from Borislav Petkov:

 - Add PREEMPT_RT maintainers

 - Fix another aspect of delayed dequeued tasks wrt determining their
   state, i.e., whether they're runnable or blocked

 - Handle delayed dequeued tasks and their migration wrt PSI properly

 - Fix the situation where a delayed dequeue task gets enqueued into a
   new class, which should not happen

 - Fix a case where memory allocation would happen while the runqueue
   lock is held, which is a no-no

 - Do not over-schedule when tasks with shorter slices preempt the
   currently running task

 - Make sure delayed to deque entities are properly handled before
   unthrottling

 - Other smaller cleanups and improvements

* tag 'sched_urgent_for_v6.12_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Add an entry for PREEMPT_RT.
  sched/fair: Fix external p->on_rq users
  sched/psi: Fix mistaken CPU pressure indication after corrupted task state bug
  sched/core: Dequeue PSI signals for blocked tasks that are delayed
  sched: Fix delayed_dequeue vs switched_from_fair()
  sched/core: Disable page allocation in task_tick_mm_cid()
  sched/deadline: Use hrtick_enabled_dl() before start_hrtick_dl()
  sched/eevdf: Fix wakeup-preempt by checking cfs_rq->nr_running
  sched: Fix sched_delayed vs cfs_bandwidth

1 files changed, 13 insertions, 2 deletions

diff --git a/kernel/task_work.c b/kernel/task_work.c
index 5d14d639ac71..c969f1f26be5 100644
--- a/kernel/task_work.c
+++ b/kernel/task_work.c
@@ -55,15 +55,26 @@ int task_work_add(struct task_struct *task, struct callback_head *work,
 		  enum task_work_notify_mode notify)
 {
 	struct callback_head *head;
+	int flags = notify & TWA_FLAGS;
 
+	notify &= ~TWA_FLAGS;
 	if (notify == TWA_NMI_CURRENT) {
 		if (WARN_ON_ONCE(task != current))
 			return -EINVAL;
 		if (!IS_ENABLED(CONFIG_IRQ_WORK))
 			return -EINVAL;
 	} else {
-		/* record the work call stack in order to print it in KASAN reports */
-		kasan_record_aux_stack(work);
+		/*
+		 * Record the work call stack in order to print it in KASAN
+		 * reports.
+		 *
+		 * Note that stack allocation can fail if TWAF_NO_ALLOC flag
+		 * is set and new page is needed to expand the stack buffer.
+		 */
+		if (flags & TWAF_NO_ALLOC)
+			kasan_record_aux_stack_noalloc(work);
+		else
+			kasan_record_aux_stack(work);
 	}
 
 	head = READ_ONCE(task->task_works);