diff --git a/src/audio/copier/copier_dai.c b/src/audio/copier/copier_dai.c
index 3861e010e902..64cbc6820dee 100644
--- a/src/audio/copier/copier_dai.c
+++ b/src/audio/copier/copier_dai.c
@@ -420,13 +420,21 @@ __cold void copier_dai_free(struct processing_module *mod)
 	assert_can_be_cold();
 
 	for (int i = 0; i < cd->endpoint_num; i++) {
-		dai_common_free(cd->dd[i]);
-		mod_free(mod, cd->dd[i]->gain_data);
-		mod_free(mod, cd->dd[i]);
+		if (cd->dd[i]) {
+			if (cd->dd[i]->gain_data) {
+				mod_free(mod, cd->dd[i]->gain_data);
+				cd->dd[i]->gain_data = NULL;
+			}
+			dai_common_free(cd->dd[i]);
+			mod_free(mod, cd->dd[i]);
+			cd->dd[i] = NULL;
+		}
 	}
 	/* only dai have multi endpoint case */
-	if (cd->multi_endpoint_buffer)
+	if (cd->multi_endpoint_buffer) {
 		buffer_free(cd->multi_endpoint_buffer);
+		cd->multi_endpoint_buffer = NULL;
+	}
 }
 
 int copier_dai_prepare(struct comp_dev *dev, struct copier_data *cd)
diff --git a/src/audio/pipeline/pipeline-params.c b/src/audio/pipeline/pipeline-params.c
index ed32fc9e3b02..9c276d26fa65 100644
--- a/src/audio/pipeline/pipeline-params.c
+++ b/src/audio/pipeline/pipeline-params.c
@@ -283,8 +283,13 @@ static int pipeline_comp_prepare(struct comp_dev *current,
 	}
 
 	err = comp_prepare(current);
-	if (err < 0 || err == PPL_STATUS_PATH_STOP)
+	if (err < 0 || err == PPL_STATUS_PATH_STOP) {
+		if (err < 0) {
+			pipe_err(current->pipeline, "comp_prepare for comp 0x%x failed %d",
+				 dev_comp_id(current), err);
+		}
 		return err;
+	}
 
 	return pipeline_for_each_comp(current, ctx, dir);
 }
diff --git a/src/platform/intel/cavs/platform.c b/src/platform/intel/cavs/platform.c
index 8a1a7c59c3b5..4c386ac7a55c 100644
--- a/src/platform/intel/cavs/platform.c
+++ b/src/platform/intel/cavs/platform.c
@@ -29,6 +29,7 @@
 #include <rtos/wait.h>
 #include <sof/platform.h>
 #include <sof/schedule/edf_schedule.h>
+#include <sof/schedule/dp_schedule.h>
 #include <sof/schedule/ll_schedule.h>
 #include <sof/schedule/ll_schedule_domain.h>
 #include <sof/trace/trace.h>
@@ -122,6 +123,12 @@ int platform_init(struct sof *sof)
 	sof->platform_timer_domain = timer_domain_init(sof->platform_timer, 0);
 	scheduler_init_ll(sof->platform_timer_domain);
 
+#if CONFIG_ZEPHYR_DP_SCHEDULER
+	ret = scheduler_dp_init();
+	if (ret < 0)
+		return ret;
+#endif
+
 	/* init the system agent */
 	trace_point(TRACE_BOOT_PLATFORM_AGENT);
 	sa_init(sof, CONFIG_SYSTICK_PERIOD);
diff --git a/src/schedule/zephyr_dp_schedule.c b/src/schedule/zephyr_dp_schedule.c
index 89a830eb14a6..9246180d7749 100644
--- a/src/schedule/zephyr_dp_schedule.c
+++ b/src/schedule/zephyr_dp_schedule.c
@@ -36,7 +36,8 @@ SOF_DEFINE_REG_UUID(dp_sched);
 /* unused with Zephyr, generates no output */
 DECLARE_TR_CTX(dp_tr, SOF_UUID(dp_sched_uuid), LOG_LEVEL_INFO);
 
-#define DP_LOCK_INIT(i, _)	Z_SEM_INITIALIZER(dp_lock[i], 1, 1)
+/* k_mutex, not k_sem: priority inheritance keeps a preempted DP holder from stalling LL */
+#define DP_LOCK_INIT(i, _)	Z_MUTEX_INITIALIZER(dp_lock[i])
 #define DP_LOCK_INIT_LIST	LISTIFY(CONFIG_MP_MAX_NUM_CPUS, DP_LOCK_INIT, (,))
 
 /* User threads don't need access to this array. Access is performed from
@@ -44,7 +45,7 @@ DECLARE_TR_CTX(dp_tr, SOF_UUID(dp_sched_uuid), LOG_LEVEL_INFO);
  * to be qualified as initialized by the gen_kobject_list.py script.
  */
 static
-STRUCT_SECTION_ITERABLE_ARRAY(k_sem, dp_lock, CONFIG_MP_MAX_NUM_CPUS) = { DP_LOCK_INIT_LIST };
+STRUCT_SECTION_ITERABLE_ARRAY(k_mutex, dp_lock, CONFIG_MP_MAX_NUM_CPUS) = { DP_LOCK_INIT_LIST };
 
 /* Each per-core instance of DP scheduler has separate structures; hence, locks are per-core.
  *
@@ -52,13 +53,13 @@ STRUCT_SECTION_ITERABLE_ARRAY(k_sem, dp_lock, CONFIG_MP_MAX_NUM_CPUS) = { DP_LOC
  */
 unsigned int scheduler_dp_lock(uint16_t core)
 {
-	k_sem_take(&dp_lock[core], K_FOREVER);
+	k_mutex_lock(&dp_lock[core], K_FOREVER);
 	return core;
 }
 
 void scheduler_dp_unlock(unsigned int key)
 {
-	k_sem_give(&dp_lock[key]);
+	k_mutex_unlock(&dp_lock[key]);
 }
 
 void scheduler_dp_grant(k_tid_t thread_id, uint16_t core)
diff --git a/zephyr/edf_schedule.c b/zephyr/edf_schedule.c
index f00ad28b217a..c418b73e92e1 100644
--- a/zephyr/edf_schedule.c
+++ b/zephyr/edf_schedule.c
@@ -86,6 +86,7 @@ static int schedule_edf_task_running(void *data, struct task *task)
 
 static int schedule_edf_task_free(void *data, struct task *task)
 {
+	k_work_cancel_delayable(&task->z_delayed_work);
 	task->state = SOF_TASK_STATE_FREE;
 	task->ops.run = NULL;
 	task->data = NULL;