diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c
index 10af28a9f2c0..b646711a45fe 100644
--- a/kernel/sched/ext/ext.c
+++ b/kernel/sched/ext/ext.c
@@ -8079,6 +8079,7 @@ static int bpf_scx_check_member(const struct btf_type *t,
 	case offsetof(struct sched_ext_ops, cgroup_init):
 	case offsetof(struct sched_ext_ops, cgroup_exit):
 	case offsetof(struct sched_ext_ops, cgroup_prep_move):
+	case offsetof(struct sched_ext_ops, cgroup_set_bandwidth):
 #endif
 	case offsetof(struct sched_ext_ops, cpu_online):
 	case offsetof(struct sched_ext_ops, cpu_offline):
@@ -11041,3 +11042,16 @@ static int __init scx_init(void)
 	return 0;
 }
 __initcall(scx_init);
+
+/*
+ * Compatibility markers for userspace. Existence of a marker function
+ * represents that the kernel supports that sched-ext feature.
+ */
+
+/*
+ * scx_compat_marker_cgroup_set_bandwidth_may_sleep: advertises that
+ * ops.cgroup_set_bandwidth() may be implemented as a sleepable callback.
+ */
+#ifdef CONFIG_EXT_GROUP_SCHED
+DEFINE_SCX_COMPAT_MARKER(cgroup_set_bandwidth_may_sleep);
+#endif	/* CONFIG_EXT_GROUP_SCHED */
diff --git a/kernel/sched/ext/internal.h b/kernel/sched/ext/internal.h
index 27bbf5e04d90..53e136a47924 100644
--- a/kernel/sched/ext/internal.h
+++ b/kernel/sched/ext/internal.h
@@ -753,7 +753,7 @@ struct sched_ext_ops {
 	 * @burst_us: bandwidth control burst
 	 *
 	 * Update @cgrp's bandwidth control parameters. This is from the cpu.max
-	 * cgroup interface.
+	 * cgroup interface. This operation may block.
 	 *
 	 * @quota_us / @period_us determines the CPU bandwidth @cgrp is entitled
 	 * to. For example, if @period_us is 1_000_000 and @quota_us is
@@ -2001,6 +2001,27 @@ struct scx_bstr_buf {
 	char			line[SCX_EXIT_MSG_LEN];
 };
 
+/* Internal helper for DEFINE_SCX_COMPAT_MARKER(). */
+#define DECLARE_SCX_COMPAT_MARKER(func)						\
+	extern void scx_compat_marker_##func(void)
+
+/**
+ * DEFINE_SCX_COMPAT_MARKER() - define a userspace capability marker
+ * @func: marker suffix; the defined symbol is scx_compat_marker_@func
+ *
+ * Emit an empty, callerless function that is retained in the kernel's BTF.
+ * Its presence is part of the kernel<->userspace contract: userspace probes
+ * scx_compat_marker_@func (e.g. via BTF) to detect that this kernel supports
+ * the corresponding feature.
+ *
+ * The leading declaration suppresses the missing-prototype warning; the
+ * trailing declaration consumes the semicolon at the use site.
+ */
+#define DEFINE_SCX_COMPAT_MARKER(func)						\
+	DECLARE_SCX_COMPAT_MARKER(func);					\
+	__used __retain void scx_compat_marker_##func(void) {}			\
+	DECLARE_SCX_COMPAT_MARKER(func)
+
 extern struct scx_sched __rcu *scx_root;
 DECLARE_PER_CPU(struct rq *, scx_locked_rq_state);