Re: [PATCH v2 5/7] btrace, gdbserver: remove the to_supports_btrace target method

["Maciej W. Rozycki" <macro@mips.com>]

Hi Markus,

 Thank you for the quick action on this problem.

On Mon, 26 Feb 2018, Andreas Arnez wrote:

> >> Process .../gdb/testsuite/outputs/gdb.base/advance/advance created; pid =
> >> 25519 Listening on port 2346 target remote 1.2.3.4:2346 Remote debugging using
> >> 1.2.3.4:2346 Reading symbols from .../lib/ld.so.1...done.
> >> 0x77fc8de0 in __start () from .../lib/ld.so.1 Protocol error: qXfer:btrace-conf
> >> (read-btrace-conf) conflicting enabled responses.
> >> (gdb) continue
> >> The program is not being run.
> >> (gdb) FAIL: gdb.base/advance.exp: can't run to main
> >> 
> >> See the attached RSP packet exchange log for details.  Please investigate.
> 
> For the record, the same happens on s390x.  It seems that you broke all
> targets without HAVE_LINUX_BTRACE.

 I suspected that might be the case.  With your future changes that touch 
generic code would you please regression-test them with another target, or 
at least ask people to do so before committing them, so that such a wide 
breakage is avoided?  Having several versions not working at all makes it 
a pain to bisect changes that may have caused regressions meanwhile.

 Also did you verify that old-GDB/new-gdbserver and new-GDB/old-gdbserver 
combinations work correctly?

> > Below is a patch to address this.  I tested it on IA by undefining HAVE_LINUX_BTRACE.
> > Does it fix the issue you reported?
> 
> I've tested your patch on s390x, and it seems to fix the problem.

 I have smoke-tested your change with `gdb.base/advance.exp' and one of 
the configurations that failed previously, and it has scored all-pass now.  
I'll schedule full testing overnight.

  Maciej