From: Tom Tromey <tromey@adacore.com>
Date: Wed, 24 Apr 2019 18:13:35 +0000 (-0600)
Subject: Fix memory leak in exception code
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=3d1cbb78936fbf2985ffd2ebf074841599ead788;p=binutils-gdb.git

Fix memory leak in exception code

PR gdb/24475 concerns a memory leak coming from gdb's exception
handling code.

The leak occurs because throw_exception_sjlj does not arrange to
destroy the exception object it is passed.  However, because
gdb_exception has a destructor, it's undefined to longjmp in this
situation.

This patch fixes the problem by avoiding the need to run any
destructors in gdb_rl_callback_handler, by making the gdb_exception
"static".

gdb/ChangeLog
2019-04-25  Tom Tromey  <tromey@adacore.com>

	PR gdb/24475:
	* event-top.c (gdb_rl_callback_handler): Make "gdb_rl_expt"
	static.
---

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 3e28e77cb73..17e10e869b8 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2019-04-25  Tom Tromey  <tromey@adacore.com>
+
+	PR gdb/24475:
+	* event-top.c (gdb_rl_callback_handler): Make "gdb_rl_expt"
+	static.
+
 2019-04-25  Tom Tromey  <tromey@adacore.com>
 
 	* xml-support.c (struct gdb_xml_parser) <set_error>: Take an
diff --git a/gdb/event-top.c b/gdb/event-top.c
index 9fa46c8ad44..3ccf136ff12 100644
--- a/gdb/event-top.c
+++ b/gdb/event-top.c
@@ -205,11 +205,15 @@ gdb_rl_callback_read_char_wrapper (gdb_client_data client_data)
 static void
 gdb_rl_callback_handler (char *rl) noexcept
 {
-  struct gdb_exception gdb_rl_expt;
+  /* This is static to avoid undefined behavior when calling longjmp
+     -- gdb_exception has a destructor with side effects.  */
+  static struct gdb_exception gdb_rl_expt;
   struct ui *ui = current_ui;
 
   try
     {
+      /* Ensure the exception is reset on each call.  */
+      gdb_rl_expt = {};
       ui->input_handler (gdb::unique_xmalloc_ptr<char> (rl));
     }
   catch (gdb_exception &ex)