Question regarding the "Jdb::handle_user_request()' function - l4-hackers

12 Mar 2013


      Hello,
the 'Jdb::enter_jdb()' function in file 'jdb.cpp' contains the following code:
// check for int $3 user debugging interface
if (foreach_cpu(&handle_user_request, true))
  {
    close_debug_console(cpu);
    leave_trap_handler(cpu);
    return 0;
  }
I'm not sure why in this case the second argument of 'foreach_cpu()' is true. I understand that it causes the result to be true only
if the 'handle_user_request()' function returned true for every currently running CPU. But I found that this can be a problem when
using the '-jdb_cmd=JS' kernel argument: if only one CPU is currently running, the result of 'foreach_cpu()' is true, but when two
CPUs are currently running, the 'handle_user_request()' function returns true only for one CPU, which makes the end result false and
causes the kernel to stop with the JDB prompt shown. Can somebody please explain?
Christian