Date: Sat, 03 Jan 2009 21:07:31 -0500 (EST) From: Terry Kennedy <terry@tmk.com> To: Peter Jeremy <peterjeremy@optushome.com.au> Cc: freebsd-stable@freebsd.org Subject: Re: rdump stuck in sbwait state (RELENG_7) Message-ID: <01N3VGDZ7EOM0008L3@tmk.com> In-Reply-To: "Your message dated Tue, 30 Dec 2008 22:12:40 %2B1100" <20081230111240.GC87057@server.vk2pj.dyndns.org> References: <01N3OFGBCXMS000125@tmk.com> <01N3OYSUCHAE000125@tmk.com>
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> Sorry, I can't think of any - by the time you see it hung, whatever
> went wrong has already happened. You might glean some insight from
> the TCP socket state (on the FreeBSD side, use 'netstat -A' to print
> the PCB address and gdb to dump the contents but I'm not sure how to
> get this data out of OpenVMS). The '-C' and '-W' options to tcpdump
> will help.
Ok, I found some time to reproduce this while capturing a trace with
tcpdump.
Here's the relevant output from netstat / kgdb:
(0:31) test4:~terry# netstat -A
Active Internet connections
Tcpcb Proto Recv-Q Send-Q Local Address Foreign Address (state)
c73eeae0 tcp4 0 0 test4.892 server.shell ESTABLISHED
[snip]
(0:32) test4:~terry# kgdb
GNU gdb 6.1.1 [FreeBSD]
[snip]
#0 0x00000000 in ?? ()
(kgdb) print * (struct tcpcb *) 0xc73eeae0
$1 = {t_segq = {lh_first = 0x0}, t_segqlen = 0, t_dupacks = 0,
t_timers = 0xc73eec24, t_inpcb = 0xc7387708, t_state = 4, t_flags = 484,
snd_una = 292841209, snd_max = 292841209, snd_nxt = 292841209,
snd_up = 292780017, snd_wl1 = 3606352422, snd_wl2 = 292841209,
iss = 3955646224, irs = 3606284909, rcv_nxt = 3606352422,
rcv_adv = 3606415910, rcv_wnd = 63488, rcv_up = 3606352422, snd_wnd = 65535,
snd_cwnd = 65535, snd_bwnd = 1073725440, snd_ssthresh = 1073725440,
snd_bandwidth = 0, snd_recover = 3955646224, t_maxopd = 1460,
t_rcvtime = 11273919, t_starttime = 11024967, t_rtttime = 0,
t_rtseq = 292839154, t_bw_rtttime = 11024966, t_bw_rtseq = 3955646224,
t_rxtcur = 230, t_maxseg = 1448, t_srtt = 145, t_rttvar = 34,
t_rxtshift = 0, t_rttmin = 30, t_rttbest = 67, t_rttupdated = 232101,
max_sndwnd = 65535, t_softerror = 0, t_oobflags = 0 '\0', t_iobc = 0 '\0',
snd_scale = 0 '\0', rcv_scale = 3 '\003', request_r_scale = 3 '\003',
ts_recent = 1207233, ts_recent_age = 11273919, ts_offset = 0,
last_ack_sent = 3606352422, snd_cwnd_prev = 0, snd_ssthresh_prev = 0,
snd_recover_prev = 0, t_badrxtwin = 0, snd_limited = 0 '\0',
snd_numholes = 0, snd_holes = {tqh_first = 0x0, tqh_last = 0xc73eebb8},
snd_fack = 0, rcv_numsacks = 0, sackblks = {{start = 0, end = 0}, {
start = 0, end = 0}, {start = 0, end = 0}, {start = 0, end = 0}, {
start = 0, end = 0}, {start = 0, end = 0}}, sack_newdata = 0,
sackhint = {nexthole = 0x0, sack_bytes_rexmit = 0}, t_rttlow = 1,
rfbuf_ts = 0, rfbuf_cnt = 0, t_pspare = {0x0, 0x0, 0x0}, t_tu = 0x0,
t_toe = 0x0}
(kgdb) q
Rather than pasting the decoded tcpdump output here, the raw capture
file is at http://www.tmk.com/transient/rdump30.gz (it is only 76KB
compressed, 270KB uncompressed). It looks to me like the remote host
(the VMS box) has correctly ack'd all outstanding data from the FreeBSD
host, but that the FreeBSD host is just sitting there for some reason.
As before, I have this sitting in the wedged state so if anyone needs
more data, I can either collect it or give you access to the system.
Terry Kennedy http://www.tmk.com
terry@tmk.com New York, NY USA
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