diff --git a/src/emu/cpu.c b/src/emu/cpu.c
index 71c8989..1222816 100644
--- a/src/emu/cpu.c
+++ b/src/emu/cpu.c
@@ -250,9 +250,8 @@ cpu_update(struct cpu *cpu)
 		err("chan_set pid failed");
 		return -1;
 	}
-	char buf[128];
 	dbg("cpu%ld sets th_running to %s",
-			cpu->gindex, value_str(gid_running, buf));
+			cpu->gindex, value_str(gid_running));
 	if (chan_set(&cpu->chan[CPU_CHAN_THRUN], gid_running) != 0) {
 		err("chan_set gid_running failed");
 		return -1;
diff --git a/src/emu/mux.c b/src/emu/mux.c
index ba2ea7f..52947da 100644
--- a/src/emu/mux.c
+++ b/src/emu/mux.c
@@ -78,8 +78,6 @@ cb_select(struct chan *sel_chan, void *ptr)
 		mux->selected = -1;
 	}
 
-	char buf[128];
-	UNUSED(buf);
 	dbg("select channel got value %s",
 			value_str(sel_value));
 
@@ -104,7 +102,7 @@ cb_select(struct chan *sel_chan, void *ptr)
 	}
 
 	dbg("setting output chan %s to %s",
-			mux->output->name, value_str(out_value, buf));
+			mux->output->name, value_str(out_value));
 
 	if (chan_set(mux->output, out_value) != 0) {
 		err("chan_set() failed");
diff --git a/src/emu/nanos6/breakdown.c b/src/emu/nanos6/breakdown.c
index f90846c..20838d9 100644
--- a/src/emu/nanos6/breakdown.c
+++ b/src/emu/nanos6/breakdown.c
@@ -105,8 +105,7 @@ select_tr(struct mux *mux, struct value value, struct mux_input **input)
 static int
 select_idle(struct mux *mux, struct value value, struct mux_input **input)
 {
-	char buf[128];
-	dbg("value is %s", value_str(value, buf));
+	dbg("value is %s", value_str(value));
 	if (value.type == VALUE_INT64 && value.i == ST_WORKER_IDLE) {
 		dbg("selecting input 1 (idle)");
 		*input = mux_get_input(mux, 1);
diff --git a/src/emu/sort.c b/src/emu/sort.c
index 45cdf95..67e1498 100644
--- a/src/emu/sort.c
+++ b/src/emu/sort.c
@@ -4,6 +4,8 @@
 //#define ENABLE_DEBUG
 
 #include "sort.h"
+#include "chan.h"
+#include "value.h"
 
 static int
 cmp_int64(const void *a, const void *b)
@@ -119,9 +121,8 @@ sort_cb_input(struct chan *in_chan, void *ptr)
 		if (value_is_equal(&last, &val))
 			continue;
 
-		char buf[128];
 		dbg("writting value %s into channel %s",
-				value_str(val, buf),
+				value_str(val),
 				sort->outputs[i].name);
 
 		if (chan_set(&sort->outputs[i], val) != 0) {
@@ -171,7 +172,7 @@ sort_init(struct sort *sort, struct bay *bay, int64_t n, const char *name)
 
 		/* No duplicate checks are done by sort module, so we
 		 * simply allow them */
-		chan_prop_set(out, CHAN_DUPLICATES, 1);
+		chan_prop_set(out, CHAN_ALLOW_DUP, 1);
 
 		if (bay_register(bay, out) != 0) {
 			err("bay_register out%ld failed", i);
diff --git a/test/unit/sort.c b/test/unit/sort.c
index f756250..6c3bb3b 100644
--- a/test/unit/sort.c
+++ b/test/unit/sort.c
@@ -2,8 +2,10 @@
  * SPDX-License-Identifier: GPL-3.0-or-later */
 
 #include "emu/sort.h"
+#include "chan.h"
 #include "common.h"
 #include "unittest.h"
+#include "value.h"
 
 #define N 10
 
@@ -14,15 +16,13 @@ check_output(struct chan *chan, struct value expected)
 	if (chan_read(chan, &out_value) != 0)
 		die("chan_read() failed for channel %s", chan->name);
 
-	char buf1[128];
 	if (!value_is_equal(&out_value, &expected)) {
-		char buf2[128];
 		die("unexpected value found %s in output (expected %s)\n",
-				value_str(out_value, buf1),
-				value_str(expected, buf2));
+				value_str(out_value),
+				value_str(expected));
 	}
 
-	err("output ok: chan=%s val=%s", chan->name, value_str(out_value, buf1));
+	err("output ok: chan=%s val=%s", chan->name, value_str(out_value));
 }
 
 static void