RE: [PATCH] btrace: avoid tp != NULL assertion

["Metzger, Markus T" <markus.t.metzger@intel.com>]

> -----Original Message-----
> From: Pedro Alves [mailto:palves@redhat.com]
> Sent: Tuesday, March 3, 2015 3:03 PM
> To: Metzger, Markus T
> Cc: gdb-patches@sourceware.org
> Subject: Re: [PATCH] btrace: avoid tp != NULL assertion


> >>> No, that wasn't the reason for replacing the assert.  There are no such
> >>> errors in the gdb.btrace suite (which is mostly single-threaded) with my
> >>> patch and I have not seen any such errors otherwise, either.
> >>
> >> Then it sounds like we're either lacking basic tests, or the threaded tests
> >> are somehow not running correctly when gdb is a 32-bit program.  I think
> >> that if you step any non-leader thread, you should see it happen.
> >> Grepping the tests, I think gdb.btrace/multi-thread-step.exp should have
> >> caught it.  My machine doesn't do btrace, so I can't try it myself...
> >>
> >> BTW, did any existing test in the testsuite catch the assertion we're
> >> fixing?
> >
> > Almost all of them when run on 32-bit systems; -m32 on 64-bit systems
> does
> > not catch this.
> 
> Right, that's why I said "when gdb is a 32-bit program".  Sounds like
> no existing test tries a "step" when not replaying then.  It'd be very
> nice to have one.  Can I convince you to add one?  :-)

The multi-thread-step.exp test does not catch it because it uses "cont",
which works fine.  When I add a "step" before the "cont", I get the
"No thread" error when using my old patch instead of your new patch.
Or I get the assert when using neither my old nor your new patch.
But then, I got the assert already on other tests.

With my patch dropped and your patch committed, what is the new
test expected to catch?

Regards,
Markus.
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