diff --git a/src/test/modules/test_dsm_registry/t/001_test_dsm_registry.pl b/src/test/modules/test_dsm_registry/t/001_test_dsm_registry.pl
index 4ad6097d1c..762489f3dd 100644
--- a/src/test/modules/test_dsm_registry/t/001_test_dsm_registry.pl
+++ b/src/test/modules/test_dsm_registry/t/001_test_dsm_registry.pl
@@ -13,12 +13,27 @@ $node->init;
 $node->start;
 
 $node->safe_psql('postgres', "CREATE DATABASE test;");
-$node->safe_psql('postgres', "CREATE EXTENSION test_dsm_registry;");
-$node->safe_psql('postgres', "SELECT set_val_in_shmem(1236);");
-
 $node->safe_psql('test', "CREATE EXTENSION test_dsm_registry;");
-my $result = $node->safe_psql('test', "SELECT get_val_in_shmem();");
-is($result, "1236", "check shmem val");
+
+my ($initial_value, $result, $custom_script);
+
+$initial_value = $node->safe_psql('test', "SELECT get_val_in_shmem();");
+
+$custom_script = File::Temp->new();
+append_to_file($custom_script, q{
+  \set val random(0, 1999)
+  SELECT increment_val_in_shmem(:val);
+  SELECT increment_val_in_shmem(-(:val));
+});
+
+$node->command_ok([ 'pgbench', '-i', 'test' ], 'Init database');
+$node->command_ok([ 'pgbench', '-t', '31', '-c', '3', '-j', '3',
+					'-f', "$custom_script", 'test' ],
+					'Change shared value simlutaneously');
+
+$result = $node->safe_psql('test', "SELECT get_val_in_shmem();");
+print("res $initial_value, $result");
+is($result, $initial_value, "Check concurrent access");
 
 $node->stop;
 
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
index 8c55b0919b..0144845afa 100644
--- a/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry--1.0.sql
@@ -3,7 +3,7 @@
 -- complain if script is sourced in psql, rather than via CREATE EXTENSION
 \echo Use "CREATE EXTENSION test_dsm_registry" to load this file. \quit
 
-CREATE FUNCTION set_val_in_shmem(val INT) RETURNS VOID
+CREATE FUNCTION increment_val_in_shmem(val INT) RETURNS VOID
 	AS 'MODULE_PATHNAME' LANGUAGE C;
 
 CREATE FUNCTION get_val_in_shmem() RETURNS INT
diff --git a/src/test/modules/test_dsm_registry/test_dsm_registry.c b/src/test/modules/test_dsm_registry/test_dsm_registry.c
index 8f78012e52..eed29a9f34 100644
--- a/src/test/modules/test_dsm_registry/test_dsm_registry.c
+++ b/src/test/modules/test_dsm_registry/test_dsm_registry.c
@@ -13,33 +13,48 @@
 #include "postgres.h"
 
 #include "fmgr.h"
+#include "common/pg_prng.h"
 #include "port/atomics.h"
 #include "storage/dsm_registry.h"
+#include "storage/lwlock.h"
 
 PG_MODULE_MAGIC;
 
-static pg_atomic_uint32 *val;
+typedef struct
+{
+	LWLock	lock;
+	uint32	value;
+} SharedState;
+
+static SharedState *extstate;
 
 static void
-init_val(void *ptr)
+init_dsm(void *ptr)
 {
-	pg_atomic_init_u32(ptr, 0);
+	SharedState *state = (SharedState *) ptr;
+
+	LWLockInitialize(&state->lock, LWLockNewTrancheId());
+	state->value = pg_prng_uint32(&pg_global_prng_state);
 }
 
 static void
 dsm_registry_attach(void)
 {
-	dsm_registry_init_or_attach("test_dsm_registry", (void **) &val,
-								sizeof(pg_atomic_uint32), init_val);
+	dsm_registry_init_or_attach("test_dsm_registry", (void **) &extstate,
+								sizeof(SharedState), init_dsm);
 }
 
-PG_FUNCTION_INFO_V1(set_val_in_shmem);
+PG_FUNCTION_INFO_V1(increment_val_in_shmem);
 Datum
-set_val_in_shmem(PG_FUNCTION_ARGS)
+increment_val_in_shmem(PG_FUNCTION_ARGS)
 {
+	uint32 increment = PG_GETARG_UINT32(0);
+
 	dsm_registry_attach();
 
-	(void) pg_atomic_exchange_u32(val, PG_GETARG_UINT32(0));
+	LWLockAcquire(&extstate->lock, LW_EXCLUSIVE);
+	extstate->value += increment;
+	LWLockRelease(&extstate->lock);
 
 	PG_RETURN_VOID();
 }
@@ -48,7 +63,13 @@ PG_FUNCTION_INFO_V1(get_val_in_shmem);
 Datum
 get_val_in_shmem(PG_FUNCTION_ARGS)
 {
+	uint32 result;
+
 	dsm_registry_attach();
 
-	PG_RETURN_UINT32(pg_atomic_fetch_add_u32(val, 0));
+	LWLockAcquire(&extstate->lock, LW_SHARED);
+	result = extstate->value;
+	LWLockRelease(&extstate->lock);
+
+	PG_RETURN_UINT32(result);
 }