Re: [PATCH][gdb/testsuite] Work around skip_prologue problems in gdb.threads/process-dies-while-detaching.exp

[Kevin Buettner <kevinb@redhat.com>]

On Tue, 2 Nov 2021 12:38:26 +0100
Tom de Vries via Gdb-patches <gdb-patches@sourceware.org> wrote:

> On 10/29/21 9:24 PM, Tom de Vries via Gdb-patches wrote:
> > Hi,
> > 
> > On powerpc64le-linux, I run into:
> > ...
> > [Inferior 1 (process 5156) exited normally]^M
> > (gdb) FAIL: gdb.threads/process-dies-while-detaching.exp: single-process: \
> >   detach: detach: continue to breakpoint: _exit (the program exited)
> > ...
> > 
> > What happens is the following:
> > - a breakpoint is set on _exit,
> > - a continue is issued
> > - the continue is supposed to hit the breakpoint, but instead
> >   the program exits.
> > 
> > I traced this down to the breakpoint on _exit being set too far from function
> > entry.  This is caused by the skip_prologue function (in rs6000-tdep.c)
> > optimistically ignoring insns it doesn't recognize.  In particular, it walks
> > past the system call instruction "sc" which initiates the actual exit.
> > 
> > While this needs fixing,  
> 
> Filed here: https://sourceware.org/bugzilla/show_bug.cgi?id=28527 .
> 
> Submitted patch here:
> https://sourceware.org/pipermail/gdb-patches/2021-November/183016.html .
> 
> Thanks,
> - Tom
> 
> > we don't want to be testing this behaviour in this
> > test-case.

Since you've fixed the problem in skip_prologue(), I'd prefer that this
testsuite patch not go in.

Kevin