Re: POLLHUP detected on devd socket

> On 23 Jan 2022, at 01:04, tech-lists <tech-lists@zyxst.net> wrote:
> context is a usb3-booting rpi4 running main-n252544-7406ec4ea99
> 
> I see this in /var/log/daemon.log:
> 
> Jan 22 13:24:54 redacted zfsd[886]: POLLHUP detected on devd socket.
> Jan 22 13:24:54 redacted zfsd[886]: Disconnecting from devd.
> Jan 22 13:24:54 redacted zfsd[886]: ConnectToDevd: Connecting to devd.
> Jan 22 13:24:54 redacted zfsd[886]: Unable to connect to devd
> Jan 22 13:24:54 redacted zfsd[886]: Disconnecting from devd.
> 
> When this happens, several other things happen:
> 
> 1. the sshd server dies. Already-established sessions still run, but    the server itself stops and no new ssh connections can be made.
> 
> 2. syslogd dies. so does exim, nginx, smartd, sshguard, pf
> 
> I don't know where to start looking for reasons for this. Is it
> a known issue? In the meantime I've turned off zfsd as it's not
> really needed in this machine's context (headless, zfs on single
> disk), from what I can tell.

Is it reproducible? ie can you trigger it post boot?

It is very strange that devd dying would kill anything else running - I have stopped and started it a lot while testing devd scripts and I haven't seen anything else break.

One idea would be to hack up devd's rc.d script and run it under ktrace and try and get some clues.

--
Daniel O'Connor
"The nice thing about standards is that there
are so many of them to choose from."
 -- Andrew Tanenbaum