From mboxrd@z Thu Jan  1 00:00:00 1970
From: Olaf Hering <olaf@aepfle.de>
Subject: Re: [Xen-users] 4.5 git: regression in xen systemd
 shutdown hangs the OS
Date: Mon, 8 Dec 2014 18:19:49 +0100
Message-ID: <20141208171949.GA1819@aepfle.de>
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To: Ian Campbell <Ian.Campbell@citrix.com>
Cc: Mark Pryor <tlviewer@yahoo.com>, Wei Liu <wei.liu2@citrix.com>, Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Ian Jackson <ian.jackson@eu.citrix.com>, xen-devel <xen-devel@lists.xen.org>, Xen-users <xen-users@lists.xen.org>
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On Fri, Dec 05, Olaf Hering wrote:

> But even with that change xendomains is hanging if it cant talk to
> xenstored for whatever  reason. The result is that the sytem hangs
> forever at shutdown. 

This looks like a bug in the tools. xl or xenstore-ls hang forever if xenstored
disappears. Looks like xs_open() is the culprit. The socket functions fail,
then it attempts to use xs_domain_dev() which happens to succeed.  Only
xenstore-ls has the '-s' option to force operating on a socket.  I wonder why
libxl does not pass XS_OPEN_SOCKETONLY? It just uses the wrappers for xs_open.

Can xenstored run in another domain?

Olaf

18:02:43.522767 stat("/var/run/xenstored/socket", {st_mode=S_IFSOCK|0600, st_size=0, ...}) = 0
18:02:43.522864 socket(PF_LOCAL, SOCK_STREAM, 0) = 3
18:02:43.522964 fcntl(3, F_GETFD)       = 0
18:02:43.523035 fcntl(3, F_SETFD, FD_CLOEXEC) = 0
18:02:43.523117 connect(3, {sa_family=AF_LOCAL, sun_path="/var/run/xenstored/socket"}, 110) = -1 ECONNREFUSED (Connection refused)
18:02:43.523224 close(3)                = 0
18:02:43.523305 stat("/proc/xen/xenbus", {st_mode=S_IFREG|0400, st_size=0, ...}) = 0
18:02:43.523393 open("/proc/xen/xenbus", O_RDWR) = 3
18:02:43.523562 brk(0)                  = 0x250c000
18:02:43.523638 brk(0x252d000)          = 0x252d000
18:02:43.523748 rt_sigaction(SIGPIPE, {SIG_IGN, [], SA_RESTORER, 0x7fc9518e3200}, {SIG_DFL, [], 0}, 8) = 0
18:02:43.523834 write(3, "\1\0\0\0\0\0\0\0\0\0\0\0\2\0\0\0", 16) = 16
18:02:43.523938 write(3, "/\0", 2