[PATCH] GDB checkpoint can't/shouldn't be possible with multiple threads on Linux

[Kevin Pouget <kevin.pouget@gmail.com>]

Hello,

as I reported in http://sourceware.org/bugzilla/show_bug.cgi?id=12628
and discussed in http://sourceware.org/ml/gdb/2011-04/msg00018.html,
GDB can't handle properly the checkpointing of an application
currently running several threads without a dedicated support.


This patch updates the thread-list and check the thread count before
doing the actual checkpoint.


(does such a patch require a test case?)

Cordially,

Kevin

-----------


diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 880781a..611aa7e 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2011-04-12 Kevin Pouget <kevin.pouget@st.com>
+
+	PR threads/12628
+	* linux-fork.c (checkpoint_command): Disallow checkpointing of
+	processes with multiple threads.
+
 2011-03-29 Kevin Pouget <kevin.pouget@st.com>

 	Allow Python notification of new object-file loadings.
diff --git a/gdb/linux-fork.c b/gdb/linux-fork.c
index 7f654af..c137604 100644
--- a/gdb/linux-fork.c
+++ b/gdb/linux-fork.c
@@ -628,6 +628,11 @@ checkpoint_command (char *args, int from_tty)
   pid_t retpid;
   struct cleanup *old_chain;

+  /* Ensure that the inferior is not multithreaded. */
+  update_thread_list () ;
+  if (thread_count () > 1)
+    error (_("checkpoint: can't checkpoint multiple threads.")) ;
+
   /* Make the inferior fork, record its (and gdb's) state.  */

   if (lookup_minimal_symbol ("fork", NULL, NULL) != NULL)