Re: rseq and gdb

* Mathieu Desnoyers:

> I suspect that gdb should ideally do something to allow it to
> single-step through rseq critical sections. In librseq [1], we emit
> the __rseq_cs_ptr_array and __rseq_exit_point_array sections to allow
> gdb to know about rseq critical sections and skip over those critical
> sections as needed. Otherwise single-stepping over each instruction of
> a rseq critical section will loop forever.

That's probably something that should be expressed in the DWARF data.

> Now that glibc plans to enable rseq by default starting with glibc 2.35,
> it appears to be a good timing to raise this topic with the gdb community.

It's less of an issue than the CRIU problem that we discussed because it
will only affect attempts to debug actually rseq-using applications.
(The CRIU problem affects everything.)  Not saying that debugging
support isn't important, just trying to put it into perspective. 8-)

Thanks,
Florian