Re: Python and target-async

[Kevin Pouget <kevin dot pouget at gmail dot com>]

> you have "set target-async on" twice. Was that a pasto?

sorry, yes the first one was wrong

here is the correct behaviour:

> (gdb) set target-async off
> (gdb) py gdb.execute("attach PID") ; gdb.execute("where")
> 0x0000003cbd0aa47e in waitpid () from /lib64/libc.so.6
> #0  0x0000003cbd0aa47e in waitpid () from /lib64/libc.so.6
> #1  0x000000000043ede2 in ?? ()
> #2  0x000000000044005f in wait_for ()
> #3  0x0000000000430c45 in execute_command_internal ()
> #4  0x0000000000430e0e in execute_command ()
> #5  0x000000000041d526 in reader_loop ()
> #6  0x000000000041ccde in main ()

and this one is wrong because the backtrace is not correctly computed:

> (gdb) set target-async on
> (gdb) py gdb.execute("attach PID") ; gdb.execute("where")
> #0  0x0000003cbd0aa47e in ?? ()
> #1  0x0000000000000000 in ?? ()
> 0x0000003cbd0aa47e in waitpid () from /lib64/libc.so.6

I expected to read:

> (gdb) set target-async on
> (gdb) py gdb.execute("attach PID") ; gdb.execute("where")
> 0x0000003cbd0aa47e in waitpid () from /lib64/libc.so.6
> #0  0x0000003cbd0aa47e in waitpid () from /lib64/libc.so.6
> #1  0x000000000043ede2 in ?? ()
> #2  0x000000000044005f in wait_for ()
> #3  0x0000000000430c45 in execute_command_internal ()
> #4  0x0000000000430e0e in execute_command ()
> #5  0x000000000041d526 in reader_loop ()
> #6  0x000000000041ccde in main ()

is it clearer this way ?

thanks,

Kevin

> On Tuesday 31 May 2011 14:51:45, Kevin Pouget wrote:
>> Hello,
>>
>> I'm facing a problem with Python not behaving correctly when
>> "target-async" is on. I'll report it in the bugtracker if someone else
>> confirms the problem:
>>
>> (replace PID by any process ID to which you can attach)
>>
>> > (gdb) set target-async on
>> > (gdb) py gdb.execute("attach PID") ; gdb.execute("where")
>> > 0x0000003cbd0aa47e in waitpid () from /lib64/libc.so.6
>> > #0 ?0x0000003cbd0aa47e in waitpid () from /lib64/libc.so.6
>> > #1 ?0x000000000043ede2 in ?? ()
>> > #2 ?0x000000000044005f in wait_for ()
>> > #3 ?0x0000000000430c45 in execute_command_internal ()
>> > #4 ?0x0000000000430e0e in execute_command ()
>> > #5 ?0x000000000041d526 in reader_loop ()
>> > #6 ?0x000000000041ccde in main ()
>> > (gdb) detach
>> > Detaching from program ...
>> > (gdb) set target-async on
>> > (gdb) py gdb.execute("attach PID") ; gdb.execute("where")
>> > #0 ?0x0000003cbd0aa47e in ?? ()
>> > #1 ?0x0000000000000000 in ?? ()
>> > 0x0000003cbd0aa47e in waitpid () from /lib64/libc.so.6
>>
>> --> the inferior can't be access normally
>>
>> the problem lies in the fact that GDB doesn't return from Python
>> between the `attach' and the `where', (the situation occurs during a
>> Python function calls as well).
>>
>> > (gdb) set target-async on
>> > (gdb) py gdb.execute("attach PID")
>> > (gdb) py gdb.execute("where")
>>
>> works correctly.
>>
>>
>> I'm not sure there is something I can do to solve it, any idea what I
>> should look for?
>>
>>
>> thanks,
>>
>> Kevin
>>
>
> --
> Pedro Alves
>