Re: [PATCH] xenstored: close socket connections on error

From: Ian Jackson <iwj@xenproject.org>
To: Manuel Bouyer <bouyer@netbsd.org>
Cc: xen-devel@lists.xenproject.org, Wei Liu <wl@xen.org>,
	Juergen Gross <jgross@suse.com>
Subject: Re: [PATCH] xenstored: close socket connections on error
Date: Wed, 3 Feb 2021 17:24:34 +0000	[thread overview]
Message-ID: <24602.56402.42441.687037@mariner.uk.xensource.com> (raw)
In-Reply-To: <20210203165421.1550-2-bouyer@netbsd.org>

Manuel Bouyer writes ("[PATCH] xenstored: close socket connections on error"):
> On error, don't keep socket connection in ignored state but close them.
> When the remote end of a socket is closed, xenstored will flag it as an
> error and switch the connection to ignored. But on some OSes (e.g.
> NetBSD), poll(2) will return only POLLIN in this case, so sockets in ignored
> state will stay open forever in xenstored (and it will loop with CPU 100%
> busy).

Juergen, I think you probably know this code the best.  Would you be
able to review this ?

I'm not sure I understand what the specific behaviour on NetBSD is
that is upsetting xenstored.  Or rather, what it is that xenstored is
using to tell when the socket should be closed.

I grepped for POLLERR and nothing came up.

Or to put it another way, is this commit

> Fixes: d2fa370d3ef9cbe22d7256c608671cdcdf6e0083

broken on Linux too ?

Ian.