I had an idea to trigger a runtime gdbstub `CONFIG_ESP_SYSTEM_GDBSTUB_RUNTIME` during application execution. The idea came about when I implemented a quick panic stub assertion:

#if CONFIG_ESP_SYSTEM_PANIC_STUB
#define ASSERT_GDB(expr) \
do { \
if (!(expr)) { \
__builtin_trap(); \
} \
} while ...