rootless: fix hang on s390x

avoid using the glibc fork() function after using directly the clone()
syscall, as it confuses glibc causing the fork() to hang in some
cases.

The issue has been observed only on s390x, and the fix was confirmed
in the issue discussion.

Closes: #25184

Signed-off-by: Giuseppe Scrivano <[email protected]>

Author: giuseppe

pkg/rootless/rootless_linux.c

@@ -658,7 +658,7 @@ create_pause_process (const char *pause_pid_file_path, char **argv)
   if (pipe (p) < 0)
     return -1;
 
-  pid = fork ();
+  pid = syscall_clone (SIGCHLD, NULL);
   if (pid < 0)
     {
       close (p[0]);
@@ -689,7 +689,7 @@ create_pause_process (const char *pause_pid_file_path, char **argv)
       close (p[0]);
 
       setsid ();
-      pid = fork ();
+      pid = syscall_clone (SIGCHLD, NULL);
       if (pid < 0)
         _exit (EXIT_FAILURE);