sched_ext: Merge branch 'for-6.14-fixes' into for-6.15

Pull for-6.14-fixes to receive:

  9360dfe4cb ("sched_ext: Validate prev_cpu in scx_bpf_select_cpu_dfl()")

which conflicts with:

  337d1b354a ("sched_ext: Move built-in idle CPU selection policy to a separate file")

Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/sched/ext.c

@@ -3250,7 +3250,6 @@ static struct task_struct *pick_task_scx(struct rq *rq)
 {
 	struct task_struct *prev = rq->curr;
 	struct task_struct *p;
-	bool prev_on_scx = prev->sched_class == &ext_sched_class;
 	bool keep_prev = rq->scx.flags & SCX_RQ_BAL_KEEP;
 	bool kick_idle = false;
 
@@ -3270,14 +3269,18 @@ static struct task_struct *pick_task_scx(struct rq *rq)
 	 * if pick_task_scx() is called without preceding balance_scx().
 	 */
 	if (unlikely(rq->scx.flags & SCX_RQ_BAL_PENDING)) {
-		if (prev_on_scx) {
+		if (prev->scx.flags & SCX_TASK_QUEUED) {
 			keep_prev = true;
 		} else {
 			keep_prev = false;
 			kick_idle = true;
 		}
-	} else if (unlikely(keep_prev && !prev_on_scx)) {
-		/* only allowed during transitions */
+	} else if (unlikely(keep_prev &&
+			    prev->sched_class != &ext_sched_class)) {
+		/*
+		 * Can happen while enabling as SCX_RQ_BAL_PENDING assertion is
+		 * conditional on scx_enabled() and may have been skipped.
+		 */
 		WARN_ON_ONCE(scx_ops_enable_state() == SCX_OPS_ENABLED);
 		keep_prev = false;
 	}
@@ -3544,7 +3547,7 @@ static void task_tick_scx(struct rq *rq, struct task_struct *curr, int queued)
 		curr->scx.slice = 0;
 		touch_core_sched(rq, curr);
 	} else if (SCX_HAS_OP(tick)) {
-		SCX_CALL_OP(SCX_KF_REST, tick, curr);
+		SCX_CALL_OP_TASK(SCX_KF_REST, tick, curr);
 	}
 
 	if (!curr->scx.slice)
@@ -3691,7 +3694,7 @@ static void scx_ops_disable_task(struct task_struct *p)
 	WARN_ON_ONCE(scx_get_task_state(p) != SCX_TASK_ENABLED);
 
 	if (SCX_HAS_OP(disable))
-		SCX_CALL_OP(SCX_KF_REST, disable, p);
+		SCX_CALL_OP_TASK(SCX_KF_REST, disable, p);
 	scx_set_task_state(p, SCX_TASK_READY);
 }
 
@@ -3720,7 +3723,7 @@ static void scx_ops_exit_task(struct task_struct *p)
 	}
 
 	if (SCX_HAS_OP(exit_task))
-		SCX_CALL_OP(SCX_KF_REST, exit_task, p, &args);
+		SCX_CALL_OP_TASK(SCX_KF_REST, exit_task, p, &args);
 	scx_set_task_state(p, SCX_TASK_NONE);
 }
 

kernel/sched/ext_idle.c

@@ -800,6 +800,9 @@ __bpf_kfunc int scx_bpf_cpu_node(s32 cpu)
 __bpf_kfunc s32 scx_bpf_select_cpu_dfl(struct task_struct *p, s32 prev_cpu,
 				       u64 wake_flags, bool *is_idle)
 {
+	if (!ops_cpu_valid(prev_cpu, NULL))
+		goto prev_cpu;
+
 	if (!check_builtin_idle_enabled())
 		goto prev_cpu;
 

tools/sched_ext/include/scx/common.bpf.h

@@ -288,8 +288,16 @@ void bpf_obj_drop_impl(void *kptr, void *meta) __ksym;
 #define bpf_obj_new(type) ((type *)bpf_obj_new_impl(bpf_core_type_id_local(type), NULL))
 #define bpf_obj_drop(kptr) bpf_obj_drop_impl(kptr, NULL)
 
-void bpf_list_push_front(struct bpf_list_head *head, struct bpf_list_node *node) __ksym;
-void bpf_list_push_back(struct bpf_list_head *head, struct bpf_list_node *node) __ksym;
+int bpf_list_push_front_impl(struct bpf_list_head *head,
+				    struct bpf_list_node *node,
+				    void *meta, __u64 off) __ksym;
+#define bpf_list_push_front(head, node) bpf_list_push_front_impl(head, node, NULL, 0)
+
+int bpf_list_push_back_impl(struct bpf_list_head *head,
+				   struct bpf_list_node *node,
+				   void *meta, __u64 off) __ksym;
+#define bpf_list_push_back(head, node) bpf_list_push_back_impl(head, node, NULL, 0)
+
 struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head) __ksym;
 struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head) __ksym;
 struct bpf_rb_node *bpf_rbtree_remove(struct bpf_rb_root *root,

tools/testing/selftests/sched_ext/init_enable_count.c

@@ -150,7 +150,7 @@ static enum scx_test_status run(void *ctx)
 
 struct scx_test init_enable_count = {
 	.name = "init_enable_count",
-	.description = "Verify we do the correct amount of counting of init, "
+	.description = "Verify we correctly count the occurrences of init, "
 		       "enable, etc callbacks.",
 	.run = run,
 };

tools/testing/selftests/sched_ext/maybe_null.c

@@ -43,7 +43,7 @@ static enum scx_test_status run(void *ctx)
 
 struct scx_test maybe_null = {
 	.name = "maybe_null",
-	.description = "Verify if PTR_MAYBE_NULL work for .dispatch",
+	.description = "Verify if PTR_MAYBE_NULL works for .dispatch",
 	.run = run,
 };
 REGISTER_SCX_TEST(&maybe_null)