diff --git a/posix/include/rtos/alloc.h b/posix/include/rtos/alloc.h
index 60dc951876e0..84751ef9f1f4 100644
--- a/posix/include/rtos/alloc.h
+++ b/posix/include/rtos/alloc.h
@@ -97,29 +97,6 @@ static inline void *rballoc(uint32_t flags, size_t bytes)
 	return rballoc_align(flags, bytes, PLATFORM_DCACHE_ALIGN);
 }
 
-/**
- * Changes size of the memory block allocated.
- * @param ptr Address of the block to resize.
- * @param flags Flags, see SOF_MEM_FLAG_...
- * @param bytes New size in bytes.
- * @param old_bytes Old size in bytes.
- * @param alignment Alignment in bytes.
- * @return Pointer to the resized memory of NULL if failed.
- */
-void *rbrealloc_align(void *ptr, uint32_t flags, size_t bytes,
-		      size_t old_bytes, uint32_t alignment);
-
-/**
- * Similar to rballoc_align(), returns resized buffer aligned to
- * PLATFORM_DCACHE_ALIGN.
- */
-static inline void *rbrealloc(void *ptr, uint32_t flags,
-			      size_t bytes, size_t old_bytes)
-{
-	return rbrealloc_align(ptr, flags, bytes, old_bytes,
-			       PLATFORM_DCACHE_ALIGN);
-}
-
 /**
  * Frees the memory block.
  * @param ptr Pointer to the memory block.
diff --git a/src/audio/buffers/comp_buffer.c b/src/audio/buffers/comp_buffer.c
index 4d62578f2fad..cc38a7dfead7 100644
--- a/src/audio/buffers/comp_buffer.c
+++ b/src/audio/buffers/comp_buffer.c
@@ -156,7 +156,16 @@ static void comp_buffer_free(struct sof_audio_buffer *audio_buffer)
 
 	struct mod_alloc_ctx *alloc = buffer->audio_buffer.alloc;
 
+#ifdef CONFIG_SOF_USERSPACE_LL
+	assert(alloc);
+	if (alloc->vreg)
+		vregion_free(alloc->vreg, buffer->stream.addr);
+	else
+		sof_heap_free(alloc->heap, buffer->stream.addr);
+#else
 	rfree(buffer->stream.addr);
+#endif
+
 	if (alloc && alloc->vreg) {
 		vregion_free(alloc->vreg, buffer);
 		if (!vregion_put(alloc->vreg))
@@ -254,7 +263,15 @@ struct comp_buffer *buffer_alloc(struct mod_alloc_ctx *alloc, size_t size, uint3
 		return NULL;
 	}
 
+#ifdef CONFIG_SOF_USERSPACE_LL
+	assert(alloc);
+	if (alloc->vreg)
+		stream_addr = vregion_alloc_align(alloc->vreg, VREGION_MEM_TYPE_INTERIM, size, align);
+	else
+		stream_addr = sof_heap_alloc(alloc->heap, flags, size, align);
+#else
 	stream_addr = rballoc_align(flags, size, align);
+#endif
 	if (!stream_addr) {
 		tr_err(&buffer_tr, "could not alloc size = %zu bytes of flags = 0x%x",
 		       size, flags);
@@ -264,7 +281,15 @@ struct comp_buffer *buffer_alloc(struct mod_alloc_ctx *alloc, size_t size, uint3
 	buffer = buffer_alloc_struct(alloc, stream_addr, size, flags, is_shared);
 	if (!buffer) {
 		tr_err(&buffer_tr, "could not alloc buffer structure");
+#ifdef CONFIG_SOF_USERSPACE_LL
+		assert(alloc);
+		if (alloc->vreg)
+			vregion_free(alloc->vreg, stream_addr);
+		else
+			sof_heap_free(alloc->heap, stream_addr);
+#else
 		rfree(stream_addr);
+#endif
 	}
 
 	return buffer;
@@ -292,7 +317,15 @@ struct comp_buffer *buffer_alloc_range(struct mod_alloc_ctx *alloc, size_t prefe
 		preferred_size += minimum_size - preferred_size % minimum_size;
 
 	for (size = preferred_size; size >= minimum_size; size -= minimum_size) {
+#ifdef CONFIG_SOF_USERSPACE_LL
+		assert(alloc);
+		if (alloc->vreg)
+			stream_addr = vregion_alloc_align(alloc->vreg, VREGION_MEM_TYPE_INTERIM, size, align);
+		else
+			stream_addr = sof_heap_alloc(alloc->heap, flags, size, align);
+#else
 		stream_addr = rballoc_align(flags, size, align);
+#endif
 		if (stream_addr)
 			break;
 	}
@@ -308,7 +341,15 @@ struct comp_buffer *buffer_alloc_range(struct mod_alloc_ctx *alloc, size_t prefe
 	buffer = buffer_alloc_struct(alloc, stream_addr, size, flags, is_shared);
 	if (!buffer) {
 		tr_err(&buffer_tr, "could not alloc buffer structure");
+#ifdef CONFIG_SOF_USERSPACE_LL
+		assert(alloc);
+		if (alloc->vreg)
+			vregion_free(alloc->vreg, stream_addr);
+		else
+			sof_heap_free(alloc->heap, stream_addr);
+#else
 		rfree(stream_addr);
+#endif
 	}
 
 	return buffer;
@@ -329,6 +370,9 @@ void buffer_zero(struct comp_buffer *buffer)
 int buffer_set_size(struct comp_buffer *buffer, uint32_t size, uint32_t alignment)
 {
 	void *new_ptr = NULL;
+#ifdef CONFIG_SOF_USERSPACE_LL
+	struct mod_alloc_ctx *alloc = buffer->audio_buffer.alloc;
+#endif
 
 	CORE_CHECK_STRUCT(&buffer->audio_buffer);
 
@@ -341,14 +385,16 @@ int buffer_set_size(struct comp_buffer *buffer, uint32_t size, uint32_t alignmen
 	if (size == audio_stream_get_size(&buffer->stream))
 		return 0;
 
-	if (!alignment)
-		new_ptr = rbrealloc(audio_stream_get_addr(&buffer->stream),
-				    buffer->flags | SOF_MEM_FLAG_NO_COPY,
-				    size, audio_stream_get_size(&buffer->stream));
+#ifdef CONFIG_SOF_USERSPACE_LL
+	assert(alloc);
+	if (alloc->vreg)
+		new_ptr = vregion_alloc_align(alloc->vreg, VREGION_MEM_TYPE_INTERIM, size, alignment);
 	else
-		new_ptr = rbrealloc_align(audio_stream_get_addr(&buffer->stream),
-					  buffer->flags | SOF_MEM_FLAG_NO_COPY, size,
-					  audio_stream_get_size(&buffer->stream), alignment);
+		new_ptr = sof_heap_alloc(alloc->heap, buffer->flags, size, alignment);
+#else
+	new_ptr = rballoc_align(buffer->flags, size, alignment);
+#endif
+
 	/* we couldn't allocate bigger chunk */
 	if (!new_ptr && size > audio_stream_get_size(&buffer->stream)) {
 		buf_err(buffer, "resize can't alloc %u bytes of flags 0x%x",
@@ -357,8 +403,18 @@ int buffer_set_size(struct comp_buffer *buffer, uint32_t size, uint32_t alignmen
 	}
 
 	/* use bigger chunk, else just use the old chunk but set smaller */
-	if (new_ptr)
-		buffer->stream.addr = new_ptr;
+	if (new_ptr) {
+#ifdef CONFIG_SOF_USERSPACE_LL
+		assert(alloc);
+		if (alloc->vreg)
+			vregion_free(alloc->vreg, audio_stream_get_addr(&buffer->stream));
+		else
+			sof_heap_free(alloc->heap, audio_stream_get_addr(&buffer->stream));
+#else
+		rfree(audio_stream_get_addr(&buffer->stream));
+#endif
+		audio_stream_set_addr(&buffer->stream, new_ptr);
+	}
 
 	buffer_init_stream(buffer, size);
 
@@ -368,10 +424,12 @@ int buffer_set_size(struct comp_buffer *buffer, uint32_t size, uint32_t alignmen
 int buffer_set_size_range(struct comp_buffer *buffer, size_t preferred_size, size_t minimum_size,
 			  uint32_t alignment)
 {
-	void *ptr = audio_stream_get_addr(&buffer->stream);
 	const size_t actual_size = audio_stream_get_size(&buffer->stream);
 	void *new_ptr = NULL;
 	size_t new_size;
+#ifdef CONFIG_SOF_USERSPACE_LL
+	struct mod_alloc_ctx *alloc = buffer->audio_buffer.alloc;
+#endif
 
 	CORE_CHECK_STRUCT(&buffer->audio_buffer);
 
@@ -389,22 +447,19 @@ int buffer_set_size_range(struct comp_buffer *buffer, size_t preferred_size, siz
 	if (preferred_size == actual_size)
 		return 0;
 
-	if (!alignment) {
-		for (new_size = preferred_size; new_size >= minimum_size;
-		     new_size -= minimum_size) {
-			new_ptr = rbrealloc(ptr, buffer->flags | SOF_MEM_FLAG_NO_COPY,
-					    new_size, actual_size);
-			if (new_ptr)
-				break;
-		}
-	} else {
-		for (new_size = preferred_size; new_size >= minimum_size;
-		     new_size -= minimum_size) {
-			new_ptr = rbrealloc_align(ptr, buffer->flags | SOF_MEM_FLAG_NO_COPY,
-						  new_size, actual_size, alignment);
-			if (new_ptr)
-				break;
-		}
+	for (new_size = preferred_size; new_size >= minimum_size;
+	     new_size -= minimum_size) {
+#ifdef CONFIG_SOF_USERSPACE_LL
+		assert(alloc);
+		if (alloc->vreg)
+			new_ptr = vregion_alloc_align(alloc->vreg, VREGION_MEM_TYPE_INTERIM, new_size, alignment);
+		else
+			new_ptr = sof_heap_alloc(alloc->heap, buffer->flags, new_size, alignment);
+#else
+		new_ptr = rballoc_align(buffer->flags, new_size, alignment);
+#endif
+		if (new_ptr)
+			break;
 	}
 
 	/* we couldn't allocate bigger chunk */
@@ -415,8 +470,18 @@ int buffer_set_size_range(struct comp_buffer *buffer, size_t preferred_size, siz
 	}
 
 	/* use bigger chunk, else just use the old chunk but set smaller */
-	if (new_ptr)
-		buffer->stream.addr = new_ptr;
+	if (new_ptr) {
+#ifdef CONFIG_SOF_USERSPACE_LL
+		assert(alloc);
+		if (alloc->vreg)
+			vregion_free(alloc->vreg, audio_stream_get_addr(&buffer->stream));
+		else
+			sof_heap_free(alloc->heap, audio_stream_get_addr(&buffer->stream));
+#else
+		rfree(audio_stream_get_addr(&buffer->stream));
+#endif
+		audio_stream_set_addr(&buffer->stream, new_ptr);
+	}
 
 	buffer_init_stream(buffer, new_size);
 
diff --git a/src/lib/alloc.c b/src/lib/alloc.c
index a6354fb0420f..aa7edeea95fd 100644
--- a/src/lib/alloc.c
+++ b/src/lib/alloc.c
@@ -38,18 +38,6 @@ void rfree(void *ptr)
 	free(ptr);
 }
 
-void *rbrealloc_align(void *ptr, uint32_t flags, size_t bytes,
-		      size_t old_bytes, uint32_t alignment)
-{
-	void *newptr = aligned_alloc(alignment, bytes);
-
-	if (!newptr)
-		return NULL;
-	memcpy(newptr, ptr, bytes > old_bytes ? old_bytes : bytes);
-	free(ptr);
-	return newptr;
-}
-
 /* TODO: all mm_pm_...() routines to be implemented for IMR storage */
 uint32_t mm_pm_context_size(void)
 {
diff --git a/src/platform/library/lib/alloc.c b/src/platform/library/lib/alloc.c
index 804c7a2f4f6e..953267ab5265 100644
--- a/src/platform/library/lib/alloc.c
+++ b/src/platform/library/lib/alloc.c
@@ -42,12 +42,6 @@ void *rballoc_align(uint32_t flags, size_t bytes,
 	return malloc(bytes);
 }
 
-void *rbrealloc_align(void *ptr, uint32_t flags, size_t bytes,
-		      size_t old_bytes, uint32_t alignment)
-{
-	return realloc(ptr, bytes);
-}
-
 void *sof_heap_alloc(struct k_heap *heap, uint32_t flags, size_t bytes,
 		     size_t alignment)
 {
diff --git a/test/cmocka/src/common_mocks.c b/test/cmocka/src/common_mocks.c
index 60b6215c4cd5..16fee8f2ff48 100644
--- a/test/cmocka/src/common_mocks.c
+++ b/test/cmocka/src/common_mocks.c
@@ -59,16 +59,6 @@ void WEAK *rzalloc(uint32_t flags,
 	return calloc(bytes, 1);
 }
 
-void WEAK *rbrealloc_align(void *ptr, uint32_t flags,
-			   size_t bytes, size_t old_bytes, uint32_t alignment)
-{
-	(void)flags;
-	(void)old_bytes;
-	(void)alignment;
-
-	return realloc(ptr, bytes);
-}
-
 void WEAK *rmalloc_align(uint32_t flags, size_t bytes, uint32_t alignment)
 {
 	(void)flags;
diff --git a/zephyr/include/rtos/alloc.h b/zephyr/include/rtos/alloc.h
index 378ff2a9f210..e21e498f0471 100644
--- a/zephyr/include/rtos/alloc.h
+++ b/zephyr/include/rtos/alloc.h
@@ -88,29 +88,6 @@ static inline void *rballoc(uint32_t flags, size_t bytes)
 	return rballoc_align(flags, bytes, PLATFORM_DCACHE_ALIGN);
 }
 
-/**
- * Changes size of the memory block allocated.
- * @param ptr Address of the block to resize.
- * @param flags Flags, see SOF_MEM_FLAG_...
- * @param bytes New size in bytes.
- * @param old_bytes Old size in bytes.
- * @param alignment Alignment in bytes.
- * @return Pointer to the resized memory of NULL if failed.
- */
-void *rbrealloc_align(void *ptr, uint32_t flags, size_t bytes,
-		      size_t old_bytes, uint32_t alignment);
-
-/**
- * Similar to rballoc_align(), returns resized buffer aligned to
- * PLATFORM_DCACHE_ALIGN.
- */
-static inline void *rbrealloc(void *ptr, uint32_t flags,
-			      size_t bytes, size_t old_bytes)
-{
-	return rbrealloc_align(ptr, flags, bytes, old_bytes,
-			       PLATFORM_DCACHE_ALIGN);
-}
-
 /**
  * Frees the memory block.
  * @param ptr Pointer to the memory block.