launchpad-dev team mailing list archive

[Jonathan Lange <jml@xxxxxxxxx>]

On Mon, Nov 7, 2011 at 8:31 PM, Gavin Panella
<gavin.panella@xxxxxxxxxxxxx> wrote:
> On 7 November 2011 14:36, Jonathan Lange <jml@xxxxxxxxx> wrote:
>> How did it hang? What was the process doing at the time?
>
> Nothing it seemed; strace showed no activity. Actually, there might
> have been a memcpy at some point. I'll try and reproduce it in a
> minute.
>

I'd try stracing it from the start, see where it hangs. If there's
process spawning going on, be sure to use the right options to follow
that. (I can't recall what they are over the top of my head).

> I'm not a debugging ace. Do you know of a good way of breaking into a
> hung process? I could step through until it hangs, which is what I
> will probably do, but that seems a little crude.
>

You can use gdb to attach to a running process, and the 'pystack'
macros[1] to get you some more Python specific help.

jml

[1] http://wiki.python.org/moin/DebuggingWithGdb