[PATCH BlueZ v4 09/20] client/agent: Fix crash on Cancel with no pending request

[Luiz Augusto von Dentz <luiz.dentz@gmail.com>]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

The auto agent replies to the requests right away, so there is no
pending request when bluetoothd cancels one, e.g. when pairing fails,
and dbus_message_unref is then called with NULL, which libdbus aborts
on:

 #5  ?? () from /usr/lib/x86_64-linux-gnu/libdbus-1.so.3
 #6  _dbus_warn_check_failed () from /usr/lib/x86_64-linux-gnu/libdbus-1.so.3
 #7  cancel_request (...) at client/agent.c:258
 #8  process_message (...) at gdbus/object.c:293

Only release the pending request if there is one, as done when the
agent is released.

Assisted-by: OpenCode:claude-opus-5.5
---
 client/agent.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/client/agent.c b/client/agent.c
index a678d5f785a9..2dd0113dc624 100644
--- a/client/agent.c
+++ b/client/agent.c
@@ -255,8 +255,14 @@ static DBusMessage *cancel_request(DBusConnection *conn,
 	bt_shell_printf("Request canceled\n");
 
 	agent_release_prompt();
-	dbus_message_unref(pending_message);
-	pending_message = NULL;
+
+	/* There is no pending request with the auto agent, which replies
+	 * right away, or if it has already been replied.
+	 */
+	if (pending_message) {
+		dbus_message_unref(pending_message);
+		pending_message = NULL;
+	}
 
 	return dbus_message_new_method_return(msg);
 }
-- 
2.55.0