Continuing in breakpoint commands hangs gdb if dashboard is enabled

Continuing in breakpoint commands hangs gdb if dashboard is enabled. You can verify this by doing the following in gdb on a sample program:

b main
commands
cont
end
run

The error that gets raised is gdb.error: Selected thread is running. and then gdb will be unresponsive. Maybe this is a duplicate of old issue #27 Thanks

[cyrus-and]

@algrebe OK it works, thanks!

So apparently scheduling a continuation command avoids the hanging. I also noticed that rendering the dashboard in a gdb.post_event handler also works but it messes with the prompt.

It’s still suboptimal as the dashboard shouldn’t be rendered in such conditions (hardly noticeable if the scrollback is discarded, default) but at least it doesn’t force the users to kill their debugging session. Anyway since this is something that requires user intervention anyway, I prefer to document this in the wiki for now and suggest to define a custom command to be used when continuing within a breakpoint’s command list:

define continue-breakpoint
python gdb.post_event(lambda: gdb.execute('continue'))
end

The usage is the following:

b main
commands
echo from breakpoint
continue-breakpoint
end

See the corresponding wiki page.

[algrebe]

@cyrus-and Thank you for your response. Yes, it does happen too late. So I took another approach this time - rather than having cont in the command, I ask the dashboard to issue the cont. This seems to work well. It probably isn’t a fix to handling cont from commands but it’s a good workaround for those who use the dashboard.

b foo
commands
dashboard -cont # <--- instead of using cont, use dashboard -cont
end

diff --git a/.gdbinit b/.gdbinit
index 8c3db0a..db5050b 100644
--- a/.gdbinit
+++ b/.gdbinit
@@ -400,6 +400,7 @@ class Dashboard(gdb.Command):
         Dashboard.OutputCommand(self)
         Dashboard.EnabledCommand(self)
         Dashboard.LayoutCommand(self)
+        Dashboard.ContinueCommand()
         # setup style commands
         Dashboard.StyleCommand(self, 'dashboard', R, R.attributes())
         # main terminal
@@ -824,6 +825,13 @@ configuration files must be placed.'''
             if output:
                 fs.write('{} -output {}\n'.format(prefix, output))
 
+    class ContinueCommand(gdb.Command):
+        def __init__(self):
+            gdb.Command.__init__(self, 'dashboard -cont', gdb.COMMAND_USER)
+
+        def invoke(self, arg, from_tty):
+            gdb.post_event(lambda: gdb.execute("cont"))
+
     class OutputCommand(gdb.Command):
         '''Set the output file/TTY for the whole dashboard or single modules.