Date: Mon, 17 Mar 2014 18:17:53 +0100 From: =?ISO-8859-1?Q?Roger_Pau_Monn=E9?= <roger.pau@citrix.com> To: Karl Pielorz <kpielorz_lst@tdx.co.uk>, <freebsd-xen@FreeBSD.org> Subject: Re: FBSD 10.0-S (r261289M) under XenServer 6.2 - Stuck sshd in urdlck? Message-ID: <53272E41.3050409@citrix.com> In-Reply-To: <4B8380EBE379080FAD3271FA@Mail-PC.tdx.co.uk> References: <4B8380EBE379080FAD3271FA@Mail-PC.tdx.co.uk>
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On 17/03/14 17:59, Karl Pielorz wrote: > > Hi, > > I setup a VM a while ago under XenServer 6.2 - it's an amd64 FBSD 10.0-S > box (based on r261289) - it's running under Xen PVHVM. > > I set it up - and left it for a while (46 days). I went to ssh to it > today, and got: > > " > ssh_exchange_identification: Connection closed by remote host > " > > Getting on to the boxes console there's lots of what look to be 'stuck' > sshd processes? > > 0 3933 895 0 20 0 84868 6944 urdlck Is - 0:00.01 sshd: unknown > [priv] (sshd) > 22 3934 3933 0 20 0 0 0 - Z - 0:00.00 <defunct> > 0 3935 3933 0 20 0 84868 6952 sbwait I - 0:00.00 sshd: unknown > [pam] (sshd) > 0 4338 895 0 20 0 84868 6944 urdlck Is - 0:00.01 sshd: unknown > [priv] (sshd) > 22 4339 4338 0 20 0 0 0 - Z - 0:00.00 <defunct> > > > Anyone know what 'urdlck' is? It seems like the process is stuck while trying to acquire a rw mutex in read mode. Could you obtain a backtrace of the process with gdb? Also a kernel-space dump might be useful, could you also run procstat -k <pid>? > > There's 126 of these processes, e.g. > > 5446 - I 0:00.00 sshd: unknown [pam] (sshd) > 5450 - Is 0:00.01 sshd: unknown [priv] (sshd) > 5452 - I 0:00.00 sshd: unknown [pam] (sshd) > 5453 - Is 0:00.01 sshd: unknown [priv] (sshd) > > > Bearing in mind the box is firewalled from ssh access, and no one (apart > from me today) has attempted to get onto the box with ssh - this is a > little concerning. Every about 5-10 connects will actually 'connect' - > the rest just result in the 'key exchange' error. > > Kernel is GENERIC with: > > options NO_ADAPTIVE_MUTEXES > options NO_ADAPTIVE_RWLOCKS > options NO_ADAPTIVE_SX > > There's nothing logged in dmesg, or syslog. > > Is there anything worth doing to this VM before I restart it - i.e. to > try and figure out what's happened? / troubleshoot? > > -Karl > > _______________________________________________ > freebsd-xen@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-xen > To unsubscribe, send any mail to "freebsd-xen-unsubscribe@freebsd.org"
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