Re: how to continue from a breakpoint in GNU/Hurd

[Yue Lu <hacklu.newborn@gmail.com>]

Hi.

On Wed, Jul 17, 2013 at 8:09 PM, Richard Braun <rbraun@sceen.net> wrote:
> On Wed, Jul 17, 2013 at 02:11:58PM +0800, Yue Lu wrote:
>> When I get the exception message, I set the EIP to the next instruction
>> (for instance 0x12345678), after resume it, I call get_thread_state(), and
>> found the EIP is still  0x12345678. The inferior never running anymore.
>
> I don't think it has anything to do with the instruction cache. Use the
> thread_info() call to determine what the suspend count is, it may have
> been incremented implicitely.

when I used thread_info() to check the suspend count, they are zero.
But I met a strange thing.
this is my code snippet:
thread_basic_info_data_t _info;
thread_basic_info_t info = &_info;
mach_msg_type_number_t info_len = THREAD_BASIC_INFO_COUNT;
error_t err =
  thread_info (thread->port, THREAD_BASIC_INFO, (int *) &info, &info_len);

after this call, the info turn out to be a  _NULL_ pointer. I think
something maybe wrong, but the err is zero.
In thread_takeover_sc_cmd() [gdb/gdb/gnu-nat.c] it has directly access
info after thread_info call, so I think this pointer never become a
NULL pointer, but in my code, it does. So I think something maybe
wrong, or this is a bug in gdb code.


--
Yue Lu (陆岳)