diff --git a/usr.bin/truss/syscalls.c b/usr.bin/truss/syscalls.c
index 31192b37a527..214138c4dd6a 100644
--- a/usr.bin/truss/syscalls.c
+++ b/usr.bin/truss/syscalls.c
@@ -473,7 +473,7 @@ static struct syscall decoded_syscalls[] = {
 	  .args = { { ShmName | IN, 0 }, { Open, 1 }, { Octal, 2 } } },
 	{ .name = "shm_open2", .ret_type = 1, .nargs = 5,
 	  .args = { { ShmName | IN, 0 }, { Open, 1 }, { Octal, 2 },
-		    { ShmFlags, 3 }, { BinString | IN, 4 } } },
+		    { ShmFlags, 3 }, { Name | IN, 4 } } },
 	{ .name = "shm_rename", .ret_type = 1, .nargs = 3,
 	  .args = { { Name | IN, 0 }, { Name | IN, 1 }, { Hex, 2 } } },
 	{ .name = "shm_unlink", .ret_type = 1, .nargs = 1,