Hi,
On Wed, May 08, 2019 at 07:11:27AM +0200, Willy Tarreau wrote:
> Hi Maciej,
>
> On Tue, May 07, 2019 at 07:08:47PM +0200, Maciej Zdeb wrote:
> > Hi,
> >
> > I've got another bug with 100% CPU on HAProxy process, it is built from
> > HEAD of 1.9 branch.
> >
> > One of processes stuck in infinite loop, admin socket is not responsive so
> > I've got information only from gdb:
> >
> > 0x0000000000484ab8 in h2_process_mux (h2c=0x2e8ff30) at src/mux_h2.c:2589
> > 2589 if (h2s->send_wait->events & SUB_CALL_UNSUBSCRIBE)
> > (gdb) n
> (...)
>
> CCing Olivier. Olivier, I'm wondering if this is not directly related to
> what you addressed with this fix merged in 2.0 but not backported :
>
> 998410a ("BUG/MEDIUM: h2: Revamp the way send subscriptions works.")
>
> From what I'm seeing there's no error, the stream is in the sending list,
> there's no blocking flag, well, everything looks OK, but we're looping
> on SUB_CALL_UNSUBSCRIBE which apprently should not if I understand it
> right. Do you think we should backport this patch ?
>
> Remaining of the trace below for reference.
>
> THanks,
> Willy
>
I can't seem to remember :)
I remember a bug involving the h2s being added to the send_list twice, and
thus leading to an infinite loop when parsing the send_list, but it was
fixed by 9a0f559676c4d309edbe42ba33197e7dd8935f1c, and backported.
For me, this one was mostly to make me happier about the code, and stop
abusing SUB_CALL_UNSUBSCRIBE, and if I didn't mention it should be backported
it's probably I considered the code in 1.9 was OK (or I just forgot), but
it's still flagged as "BUG" too (but that could be me having "BUG/MEDIUM"
hardcoded in my finger).
I think that patch is safe to backport anyway, but I wouldn't swear it solves
Maciej's issue.
Regards,
Olivier
