diff --git a/libc-top-half/musl/src/signal/kill.c b/libc-top-half/musl/src/signal/kill.c
index ca43eb8a1..ea85ea7d5 100644
--- a/libc-top-half/musl/src/signal/kill.c
+++ b/libc-top-half/musl/src/signal/kill.c
@@ -2,6 +2,7 @@
 #ifdef __wasilibc_unmodified_upstream
 #include "syscall.h"
 #else
+#include <errno.h>
 #include <wasi/api.h>
 #endif
 
@@ -11,6 +12,10 @@ int kill(pid_t pid, int sig)
 	return syscall(SYS_kill, pid, sig);
 #else
 	int r = __wasi_proc_signal(pid, (__wasi_signal_t)sig);
-	return r;
+	if (r != 0) {
+		errno = r;
+		return -1;
+	}
+	return 0;
 #endif
 }
\ No newline at end of file