Aw: Re: how to debug gdb?

[Uwe]

> Gesendet: Donnerstag, 06. Mai 2021 um 12:42 Uhr
> Von: "Tomasz Gajewski" <tomga at wp.pl>
> An: users at lists.genode.org
> Betreff: Re: how to debug gdb?
>
> 
> Hi Alexander,
> 
> 
> Alexander Tormasov via users <users at lists.genode.org> writes:
> 
> > the only workable solution with own gdbserver inside qemu with nova in
> > this moment hangs, as described, in some attempt to upgrade quota:
> > [init -> gdb_monitor] upgrading quota donation for PD session (0 bytes, 4 caps)
> > [init] child "gdb_monitor" requests resources: ram_quota=0, cap_quota=4
> >
> > when i update a bit run file it give me another message before hang (while I give 3500 caps):
> > [init] child "gdb_monitor" requests resources: cap_quota=2
> 
> Is it possible that you missed message from Christian Prochasa he sent
> on April 9th? Increasing that constant helped me to further with
> debugging service using gdb_monitor on Nova in qemu.
> 
> > suggested solution with nova inside qemu -s somehow work except that
> > it do not see threads!  Now I found that for UP even in the very
> > beginning gdb show only CPU0 single thread (while genode do create at
> > least 2 - main and for signals).  for 2 CPU version it show only 2 of
> > them/etc.
> >
> > so… still not clear for me where it the best solution to continue
> >
> > so far qemu -s works in faster way, while it do not see internal nova threads…
> > Can we somehow force qemu to show nova threads?
> 
> Currently I stumbled on problem with threads too. I know that creating
> thread using 'pthread_create' in debugged code does not raise any error
> but after this call number of thread visible in gdb (using 'info
> thread') does not change and breakpoint set inside a function assigned
> for thread is never triggered.
> 
> 
> Does anybody know if it is a sign of not creating thread at all or some
> deficiency in 'gdb_monitor' that fails to update presented list of
> threads? From the behavior it seems it is a first option.
> 
Qemu is not supposed to create threads. All threads in qemu are created at startup. For every (emulated) CPU core one thread, never more. 
For OS level threads you need a gdb server at OS level. 
> Another question is if it is supposed to work and it doesn't only
> because of some error or gdb_monitor lacks this functionality
> completely?
> 
> 
> Regards
> Tomasz Gajewski
> 
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