Only allow QUIT on the main thread

Pedro pointed out that gdb worker threads should not react to quits.
While I don't think that the new DWARF reader can call QUIT from a
worker thread (and I don't think the existing minsym threading code
can either), it seems safest to address this before checking in the
new code.  This patch arranges for the QUIT macro to only work on the
main thread.

diff --git a/gdb/run-on-main-thread.c b/gdb/run-on-main-thread.c
index ea633d9d2d0ed271de7a978da2db50ccdb7d22c1..eb22310f5c0fce241c8c2f36a4f8f5179249e344 100644 (file)
--- a/gdb/run-on-main-thread.c
+++ b/gdb/run-on-main-thread.c
@@ -20,6 +20,7 @@
 #include "run-on-main-thread.h"
 #include "ser-event.h"
 #if CXX_STD_THREAD
+#include <thread>
 #include <mutex>
 #endif
 #include "gdbsupport/event-loop.h"
@@ -38,6 +39,10 @@ static std::vector<std::function<void ()>> runnables;
 
 static std::mutex runnable_mutex;
 
+/* The main thread.  */
+
+static std::thread::id main_thread;
+
 #endif
 
 /* Run all the queued runnables.  */
@@ -89,10 +94,25 @@ run_on_main_thread (std::function<void ()> &&func)
   serial_event_set (runnable_event);
 }
 
+/* See run-on-main-thread.h.  */
+
+bool
+is_main_thread ()
+{
+#if CXX_STD_THREAD
+  return std::this_thread::get_id () == main_thread;
+#else
+  return true;
+#endif
+}
+
 void _initialize_run_on_main_thread ();
 void
 _initialize_run_on_main_thread ()
 {
+#if CXX_STD_THREAD
+  main_thread = std::this_thread::get_id ();
+#endif
   runnable_event = make_serial_event ();
   add_file_handler (serial_event_fd (runnable_event), run_events, nullptr,
                    "run-on-main-thread");

diff --git a/gdb/run-on-main-thread.h b/gdb/run-on-main-thread.h
index 0bfe0b7456a9240021a7c052587c08960d8a2121..888328e7a5163a2080acc01df0a4daf8a27649d8 100644 (file)
--- a/gdb/run-on-main-thread.h
+++ b/gdb/run-on-main-thread.h
@@ -25,4 +25,8 @@
 
 extern void run_on_main_thread (std::function<void ()> &&);
 
+/* Return true on the main thread.  */
+
+extern bool is_main_thread ();
+
 #endif /* GDB_RUN_ON_MAIN_THREAD_H */

diff --git a/gdb/utils.c b/gdb/utils.c
index 2df9b1d7dcf42e04c2ff110dcd0b729892b26cef..9ca268ad07feb145b156ccabc377c1856431ed34 100644 (file)
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -78,6 +78,7 @@
 #include "bt-utils.h"
 #include "gdbsupport/buildargv.h"
 #include "pager.h"
+#include "run-on-main-thread.h"
 
 void (*deprecated_error_begin_hook) (void);
 
@@ -681,6 +682,9 @@ quit (void)
 void
 maybe_quit (void)
 {
+  if (!is_main_thread ())
+    return;
+
   if (sync_quit_force_run)
     quit ();