Merge tag 'sched_ext-for-6.17-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext

Pull sched_ext fixes from Tejun Heo:

 - Fix a subtle bug during SCX enabling where a dead task skips init
   but doesn't skip sched class switch leading to invalid task state
   transition warning

 - Cosmetic fix in selftests

* tag 'sched_ext-for-6.17-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
  selftests/sched_ext: Remove duplicate sched.h header
  sched/ext: Fix invalid task state transitions on class switch

Author: torvalds

kernel/sched/ext.c

@@ -5749,6 +5749,9 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link)
 			__setscheduler_class(p->policy, p->prio);
 		struct sched_enq_and_set_ctx ctx;
 
+		if (!tryget_task_struct(p))
+			continue;
+
 		if (old_class != new_class && p->se.sched_delayed)
 			dequeue_task(task_rq(p), p, DEQUEUE_SLEEP | DEQUEUE_DELAYED);
 
@@ -5761,6 +5764,7 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link)
 		sched_enq_and_set_task(&ctx);
 
 		check_class_changed(task_rq(p), p, old_class, p->prio);
+		put_task_struct(p);
 	}
 	scx_task_iter_stop(&sti);
 	percpu_up_write(&scx_fork_rwsem);

tools/testing/selftests/sched_ext/hotplug.c

@@ -6,7 +6,6 @@
 #include <bpf/bpf.h>
 #include <sched.h>
 #include <scx/common.h>
-#include <sched.h>
 #include <sys/wait.h>
 #include <unistd.h>