diff --git a/lldb/tools/debugserver/source/MacOSX/MachProcess.mm b/lldb/tools/debugserver/source/MacOSX/MachProcess.mm
--- a/lldb/tools/debugserver/source/MacOSX/MachProcess.mm
+++ b/lldb/tools/debugserver/source/MacOSX/MachProcess.mm
@@ -3307,7 +3307,7 @@
     return INVALID_NUB_PROCESS;
 
   flags = POSIX_SPAWN_START_SUSPENDED | POSIX_SPAWN_SETSIGDEF |
-          POSIX_SPAWN_SETSIGMASK;
+          POSIX_SPAWN_SETSIGMASK | POSIX_SPAWN_SETPGROUP;
   if (disable_aslr)
     flags |= _POSIX_SPAWN_DISABLE_ASLR;