Merge tag 'sched_urgent_for_v6.13_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler fixes from Borislav Petkov:

 - Remove wrong enqueueing of a task for a later wakeup when a task
   blocks on a RT mutex

 - Do not setup a new deadline entity on a boosted task as that has
   happened already

 - Update preempt= kernel command line param

 - Prevent needless softirqd wakeups in the idle task's context

 - Detect the case where the idle load balancer CPU becomes busy and
   avoid unnecessary load balancing invocation

 - Remove an unnecessary load balancing need_resched() call in
   nohz_csd_func()

 - Allow for raising of SCHED_SOFTIRQ softirq type on RT but retain the
   warning to catch any other cases

 - Remove a wrong warning when a cpuset update makes the task affinity
   no longer a subset of the cpuset

* tag 'sched_urgent_for_v6.13_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking: rtmutex: Fix wake_q logic in task_blocks_on_rt_mutex
  sched/deadline: Fix warning in migrate_enable for boosted tasks
  sched/core: Update kernel boot parameters for LAZY preempt.
  sched/core: Prevent wakeup of ksoftirqd during idle load balance
  sched/fair: Check idle_cpu() before need_resched() to detect ilb CPU turning busy
  sched/core: Remove the unnecessary need_resched() check in nohz_csd_func()
  softirq: Allow raising SCHED_SOFTIRQ from SMP-call-function on RT kernel
  sched: fix warning in sched_setaffinity
  sched/deadline: Fix replenish_dl_new_period dl_server condition

1 files changed, 11 insertions, 4 deletions

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 8b41bd13cc3d..4dae6ac2e83f 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -280,17 +280,24 @@ static inline void invoke_softirq(void)
 		wakeup_softirqd();
 }
 
+#define SCHED_SOFTIRQ_MASK	BIT(SCHED_SOFTIRQ)
+
 /*
  * flush_smp_call_function_queue() can raise a soft interrupt in a function
- * call. On RT kernels this is undesired and the only known functionality
- * in the block layer which does this is disabled on RT. If soft interrupts
- * get raised which haven't been raised before the flush, warn so it can be
+ * call. On RT kernels this is undesired and the only known functionalities
+ * are in the block layer which is disabled on RT, and in the scheduler for
+ * idle load balancing. If soft interrupts get raised which haven't been
+ * raised before the flush, warn if it is not a SCHED_SOFTIRQ so it can be
  * investigated.
  */
 void do_softirq_post_smp_call_flush(unsigned int was_pending)
 {
-	if (WARN_ON_ONCE(was_pending != local_softirq_pending()))
+	unsigned int is_pending = local_softirq_pending();
+
+	if (unlikely(was_pending != is_pending)) {
+		WARN_ON_ONCE(was_pending != (is_pending & ~SCHED_SOFTIRQ_MASK));
 		invoke_softirq();
+	}
 }
 
 #else /* CONFIG_PREEMPT_RT */