Re: Stuck gnat1 processes

["Carlos O'Donell" <carlos@xxxxxxxxxxxxxxxx>]

On Thu, Jun 9, 2011 at 11:01 PM, John David Anglin
<dave@xxxxxxxxxxxxxxxxxx> wrote:
> On Thu, 09 Jun 2011, Carlos O'Donell wrote:
>
>> This looks like a combination of multiple bugs, the process is
>> probably dead, or not running, which is why gdb can't do anything with
>> it. I'm surprised the ptrace API isn't returning some more diagnostics
>> about the stuck process.
>
> Why do you think the processes are dead or not running?  Top thinks
> they are running at 100% CPU.  The general system responsiveness
> seemed like full load.

If it's not dead, and running, why do you always attach and show $pc
at the same place?

This is either a ptrace bug, a gdb bug, or a kernel bug.

Either:

* Ptrace is incorrectly always returning $pc at a fixed location.

* Process is stuck faulting, running a signal handler, and returning
to the fault location.
- Does gnat it have a signal handler?

* Kernel is not running the process therefore whenever you attach it's
in the same place.

* gdb bug causes the process to always show as being in the same place.

You have to start ruling these out.

Cheers,
Carlos.
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