Index: sys/compat/linux/linux_misc.c
===================================================================
--- sys/compat/linux/linux_misc.c
+++ sys/compat/linux/linux_misc.c
@@ -1096,6 +1096,7 @@
 {
 	idtype_t idtype;
 	int error, options;
+	pid_t id;
 
 	if (args->options & ~(LINUX_WNOHANG | LINUX_WNOWAIT | LINUX_WEXITED |
 	    LINUX_WSTOPPED | LINUX_WCONTINUED | __WCLONE | __WNOTHREAD | __WALL))
@@ -1107,6 +1108,7 @@
 		options |= WEXITED | WTRAPPED | WUNTRACED |
 		    WCONTINUED | WLINUXCLONE;
 
+	id = args->id;
 	switch (args->idtype) {
 	case LINUX_P_ALL:
 		idtype = P_ALL;
@@ -1117,8 +1119,13 @@
 		idtype = P_PID;
 		break;
 	case LINUX_P_PGID:
-		if (args->id <= 0)
+		if (args->id < 0)
 			return (EINVAL);
+		if (args->id == 0) {
+			error = kern_getpgid(td, args->id, &id);
+			if (error != 0)
+				return (error);
+		}
 		idtype = P_PGID;
 		break;
 	case LINUX_P_PIDFD:
@@ -1128,7 +1135,7 @@
 		return (EINVAL);
 	}
 
-	error = linux_common_wait(td, idtype, args->id, NULL, options,
+	error = linux_common_wait(td, idtype, id, NULL, options,
 	    args->rusage, args->info);
 	td->td_retval[0] = 0;