Hello!

On Thu, Dec 19, 2019 at 11:45:28AM +0300, Ruslan Ermilov wrote:

> On Wed, Dec 18, 2019 at 06:35:35PM +0100, Gábor Boskovits wrote:
> > Hello Maxim,
> >
> > Maxim Dounin <mdounin@mdounin.ru> ezt írta (időpont: 2019. dec. 18.,
> > Sze, 18:24):
> > >
> > > Hello!
> > >
> > > On Mon, Dec 16, 2019 at 03:02:37PM +0100, Gábor Boskovits wrote:
> > >
> > > > On berlin.guix.gnu.org we observed a regression upon upgrading nginx
> > > > to 1.17.5. The problem was, when pipelining request to a proxy using
> > > > tls, we suddenly started to get 408 client timeouts, manifesting in
> > > > dropped connections. Currently we worked around the issue by
> > > > downgrading to 1.17.4. I have collected some information about the
> > > > problem here:
> > > > https://gitlab.com/g_bor/fix-nginx-tls
> > > > It contains the logs from the good and the bad version, a full nginx
> > > > config, some info about how nginx was built. I managed to bisect the
> > > > problem down to changeset 9d2ad2fb4423, which introduced the problem.
> > > > Any help in further debuggin this would be greatly appreciated.
> > >
> > > Thanks for the report, it indeed looks like a bug introduced
> > > in 9d2ad2fb4423.
> > >
> > > The problem is that c->read->handler is overwritted when switching
> > > to the next pipelined request, ngx_ssl_next_read_handler() is not
> > > called, and c->read->ready remains not set. I'll take a look how
> > > to fix it properly.
> >
> > Thanks for having a look.
> >
> > Please keep me updated when the fix gets applied.
> >
> > >
> > > Note well that a simpler workaround might be to build nginx with
> > > the --with-cc-opt="-DNGX_HAVE_FIONREAD=0" configure argument, this
> > > will disable the code in question on systems not using kqueue.
> > >
> >
> > Thanks for the information, we do not yet support any systems with kqueue yet,
> > so this might work temporarily.
>
> Maxim means e.g. Linux when he says "on systems not using kqueue".
> There's no such problem on systems with kqueue, e.g. FreeBSD.

Not really. I meant the workaround in question won't work on
systems with kqueue. The problem itself is present with kqueue as
well.

That is, the workaround in question will work fine on Linux, but
won't work on FreeBSD (unless you configure nginx to use select or
poll, but probably this isn't a good idea).

--
Maxim Dounin
http://mdounin.ru/
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