Index: lldb/lit/lit-lldb-init.in
===================================================================
--- lldb/lit/lit-lldb-init.in
+++ lldb/lit/lit-lldb-init.in
@@ -1,3 +1,4 @@
 # LLDB init file for the LIT tests.
 settings set symbols.enable-external-lookup false
+settings set plugin.process.gdb-remote.packet-timeout 300
 settings set interpreter.echo-comment-commands false
Index: lldb/packages/Python/lldbsuite/test/api/multithreaded/driver.cpp.template
===================================================================
--- lldb/packages/Python/lldbsuite/test/api/multithreaded/driver.cpp.template
+++ lldb/packages/Python/lldbsuite/test/api/multithreaded/driver.cpp.template
@@ -32,6 +32,7 @@
   SBDebugger::Initialize();
   SBDebugger dbg = SBDebugger::Create();
   dbg.HandleCommand("settings set symbols.enable-external-lookup false");
+  dbg.HandleCommand("settings set plugin.process.gdb-remote.packet-timeout 300");
 
   try {
     if (!dbg.IsValid())
Index: lldb/packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestNoWatchpointSupportInfo.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestNoWatchpointSupportInfo.py
+++ lldb/packages/Python/lldbsuite/test/functionalities/gdb_remote_client/TestNoWatchpointSupportInfo.py
@@ -21,6 +21,7 @@
             def threadStopInfo(self, threadnum):
                 if threadnum == 0x1ff0d:
                     return "T02thread:1ff0d;thread-pcs:10001bc00;"
+                return ""
 
             def setBreakpoint(self, packet):
                 if packet.startswith("Z2,"):
Index: lldb/packages/Python/lldbsuite/test/lldbtest.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/lldbtest.py
+++ lldb/packages/Python/lldbsuite/test/lldbtest.py
@@ -716,7 +716,9 @@
         else:
             self.lldbVSCodeExec = None
 
-        self.lldbOption = "-o 'settings set symbols.enable-external-lookup false'"
+        self.lldbOption = (
+            "-o 'settings set symbols.enable-external-lookup false'"
+            " -o 'settings set plugin.process.gdb-remote.packet-timeout 300'")
 
         # If we spawn an lldb process for test (via pexpect), do not load the
         # init file unless told otherwise.
@@ -1864,6 +1866,9 @@
         # differ in the debug info, which is not being hashed.
         self.runCmd('settings set symbols.enable-external-lookup false')
 
+        # Testsuite runs in parallel and the host can have also other load.
+        self.runCmd('settings set plugin.process.gdb-remote.packet-timeout 300')
+
         # Disable color.
         self.runCmd("settings set use-color false")
 
Index: lldb/packages/Python/lldbsuite/test/tools/lldb-vscode/vscode.py
===================================================================
--- lldb/packages/Python/lldbsuite/test/tools/lldb-vscode/vscode.py
+++ lldb/packages/Python/lldbsuite/test/tools/lldb-vscode/vscode.py
@@ -448,7 +448,8 @@
         if trace:
             args_dict['trace'] = trace
         args_dict['initCommands'] = [
-            'settings set symbols.enable-external-lookup false']
+            'settings set symbols.enable-external-lookup false',
+            'settings set plugin.process.gdb-remote.packet-timeout 300']
         if initCommands:
             args_dict['initCommands'].extend(initCommands)
         if preRunCommands:
@@ -579,7 +580,8 @@
         if trace:
             args_dict['trace'] = trace
         args_dict['initCommands'] = [
-            'settings set symbols.enable-external-lookup false']
+            'settings set symbols.enable-external-lookup false',
+            'settings set plugin.process.gdb-remote.packet-timeout 300']
         if initCommands:
             args_dict['initCommands'].extend(initCommands)
         if preRunCommands:
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -211,6 +211,7 @@
     // may take a little longer than normal to receive a reply.  Wait at least
     // 6 seconds for a reply to this packet.
 
+    // 6 secs are still not sufficient; this line is not to be checked-in.
     ScopedTimeout timeout(*this, std::max(GetPacketTimeout(), seconds(6)));
 
     StringExtractorGDBRemote response;
Index: lldb/tools/lldb-test/lldb-test.cpp
===================================================================
--- lldb/tools/lldb-test/lldb-test.cpp
+++ lldb/tools/lldb-test/lldb-test.cpp
@@ -976,6 +976,12 @@
 
   auto Dbg = lldb_private::Debugger::CreateInstance();
   ModuleList::GetGlobalModuleListProperties().SetEnableExternalLookup(false);
+  // Unable to get:
+  // GetGlobalPluginProperties()->SetPacketTimeout(std::chrono::seconds(300));
+  CommandReturnObject Result;
+  Dbg->GetCommandInterpreter().HandleCommand(
+      "settings set plugin.process.gdb-remote.packet-timeout 300",
+      /*add_to_history*/ eLazyBoolNo, Result);
 
   if (!opts::Log.empty())
     Dbg->EnableLog("lldb", {"all"}, opts::Log, 0, errs());