Re: Re: [PATCH v3 3/3] tests/tcg: Add the PROT_NONE gdbstub test

[Ilya Leoshkevich]

On Mon, Jan 22, 2024 at 03:54:32PM +0000, Alex Bennée wrote:
> Ilya Leoshkevich <iii@linux.ibm.com> writes:
> 
> > Make sure that qemu gdbstub, like gdbserver, allows reading from and
> > writing to PROT_NONE pages.
> >
> > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> > ---
> >  tests/tcg/multiarch/Makefile.target      |  9 +++++-
> >  tests/tcg/multiarch/gdbstub/prot-none.py | 22 +++++++++++++
> >  tests/tcg/multiarch/prot-none.c          | 40 ++++++++++++++++++++++++
> >  3 files changed, 70 insertions(+), 1 deletion(-)
> >  create mode 100644 tests/tcg/multiarch/gdbstub/prot-none.py
> >  create mode 100644 tests/tcg/multiarch/prot-none.c

[...]

> > +def run_test():
> > +    """Run through the tests one by one"""
> > +    gdb.Breakpoint("break_here")
> > +    gdb.execute("continue")
> > +    val = gdb.parse_and_eval("*(char[2] *)q").string()
> 
> Better traceback:
> 
>   Breakpoint 1, break_here (q=0x400000802fff) at 
> /home/alex/lsrc/qemu.git/tests/tcg/multiarch/prot-none.c:14
>   14      }
>   GDB Exception:
>   Traceback (most recent call last):
>     File "/home/alex/lsrc/qemu.git/tests/guest-debug/test_gdbstub.py", line 
> 42, in main
>       test()
>     File "./tests/tcg/multiarch/gdbstub/prot-none.py", line 14, in run_test
>       val = gdb.parse_and_eval("*(char[2] *)q").string()
>             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>   gdb.MemoryError: Cannot access memory at address 0x400000802fff
>   Python 3.11.2 (main, Mar 13 2023, 12:18:29) [GCC 12.2.0] on linux
>   Type "help", "copyright", "credits" or "license" for more information.
>   (InteractiveConsole)
>   >>> 

Thanks for the debug output. This shows that the feature being tested
doesn't work (the value of `q` looks sane to me). May I ask what host
distro is this? I tried on x86_64 Fedora 38 and x86_64 Ubuntu 22.04 so
far, and the test was successful.

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