gdb: Log CommandReadMemory failure

monitor backtrace (mo bt)
monitor registers (mo reg)
monitor get info

src/Ryujinx.HLE/Debugger/Debugger.cs

@@ -32,6 +32,7 @@ namespace Ryujinx.HLE.Debugger
         private Thread DebuggerThread;
         private Thread MessageHandlerThread;
         private bool _shuttingDown = false;
+        private ManualResetEventSlim _breakHandlerEvent = new ManualResetEventSlim(false);
 
         private ulong? cThread;
         private ulong? gThread;
@@ -237,6 +238,7 @@ namespace Ryujinx.HLE.Debugger
                         case ThreadBreakMessage { Context: var ctx }:
                             DebugProcess.DebugStop();
                             gThread = cThread = ctx.ThreadUid;
+                            _breakHandlerEvent.Set();
                             Reply($"T05thread:{ctx.ThreadUid:x};");
                             break;
 
@@ -860,6 +862,9 @@ namespace Ryujinx.HLE.Debugger
             }
             catch (InvalidMemoryRegionException)
             {
+                // InvalidAccessHandler will show an error message, we log it again to tell user the error is from GDB (which can be ignored)
+                // TODO: Do not let InvalidAccessHandler show the error message
+                Logger.Notice.Print(LogClass.GdbStub, $"GDB failed to read memory at 0x{addr:X16}");
                 ReplyError();
             }
         }
@@ -1266,15 +1271,20 @@ namespace Ryujinx.HLE.Debugger
                 Messages.Add(new KillMessage());
                 MessageHandlerThread.Join();
                 Messages.Dispose();
+                _breakHandlerEvent.Dispose();
             }
         }
 
         public void BreakHandler(IExecutionContext ctx, ulong address, int imm)
         {
-            Logger.Notice.Print(LogClass.GdbStub, $"Break hit on thread {ctx.ThreadUid} at pc {address:x016}");
-
-            Messages.Add(new ThreadBreakMessage(ctx, address, imm));
             DebugProcess.DebugInterruptHandler(ctx);
+
+            _breakHandlerEvent.Reset();
+            Messages.Add(new ThreadBreakMessage(ctx, address, imm));
+            // Messages.Add can block, so we log it after adding the message to make sure user can see the log at the same time GDB receives the break message
+            Logger.Notice.Print(LogClass.GdbStub, $"Break hit on thread {ctx.ThreadUid} at pc {address:x016}");
+            // Wait for the process to stop before returning to avoid BreakHander being called multiple times from the same breakpoint
+            _breakHandlerEvent.Wait(5000);
         }
 
         public void StepHandler(IExecutionContext ctx)