freebsd stable - Mar 2021 - FreeBSD 13.0-RC4 and Nginx process "stuck" during restart

> On 30 Mar 2021, at 18:40, Jonathan T. Looney <jtl at freebsd.org>
wrote:
> 
> Yes, it could be related. Because of the timing of when we first saw the
behavior, I assumed the trigger for the behavior (which remains unknown) only
existed in main. However, it is possible that this behavior is now being
triggered in 13.0.
> 
> Are you able to reliably reproduce this? I was never able to do that. A
reliable reproduction may help narrow down the change which triggered this
behavior.
> 
> I can certainly MFC the patch to stable/13. re@ will need to decide whether
to admit it to the release branch.
> 
> Jonathan
Hello Jonathan,

I have 100+ nginx servers and I can reproduce it in many of them. It doesn't
happen always in the same servers. Also after a "killlall -9 nginx
&& service nginx restart"  a second "service nginx
restart" few seconds after the first restart completes successfully. I
believe it needs few minutes/hours running nginx before the restart
"stuck" in "Waiting for PIDS: 85499."

Did you notice it with nginx too or something else? I also run monit, bind,
dovecot, postfix, mysql, php-fpm and pure-ftpd and didn't notice any restart
of these services to "stuck".

On Tue, Mar 30, 2021 at 12:01 PM Christos Chatzaras <chris at
cretaforce.gr>
wrote:
>
> Did you notice it with nginx too or something else? I also run monit,
> bind, dovecot, postfix, mysql, php-fpm and pure-ftpd and didn't notice
any
> restart of these services to "stuck".
>
Yes, we noticed it in Nginx; however, we only saw it on a very small
percentage of servers. I think we might have seen one other instance with a
different process, but I can't remember for sure.

Jonathan