Potential upstart bug with overflowing stanzas

[Garrett Cooper]

On Wed, Oct 29, 2008 at 2:37 AM, Scott James Remnant <scott at netsplit.com> wrote:
> On Tue, 2008-10-28 at 17:32 -0700, Garrett Cooper wrote:
>
>> After executing this example multiple times (~10 does the trick), I've
>> gotten init + libdbus to become unresponsive to a large degree, where
>> it starts printing out "latency error messages". I've seen this occur
>> on QEMU/ppc and I haven't been able to replicate the issue on MIPS
>> (yet). I have however seen the same error message when jamming a lot
>> of DBUS requests to upstart using our in-house client.
>>
> The author string isn't transmitted across libdbus, so I'm not sure
> that's relevant here?
>
> You're repeatedly allocating a 300KB author string?  That'll be simply
> thrashing memory?
>
> Scott

But it's allocating memory and waiting for a reply from the dbus shmem
bindings though -- that's where the issue can be seen.
As I said, I haven't been able to get the issue to pop up on a real
target, but the performance issue pops up with single proc versions of
emulators -- where time + memory is more constrained than conventional
systems. So, I'm sure I could get the issue to pop up on a real target
by raising the value size to an artificially large value, but
shouldn't upstart be capping the amount of data it's passing through
with its parser via strn* or strl*?
Thanks,
-Garrett