ssh hangs when X programs exit

To: debian-user@lists.debian.org
Cc: 116888@bugs.debian.org
Subject: ssh hangs when X programs exit
From: Bill Wohler <wohler@newt.com>
Date: Thu, 08 Nov 2001 10:14:55 -0800
Message-id: <[🔎] 200111081814.fA8IEtPU026992@gbr.newt.com>
  I just started noticing that ssh hangs with X commands. I believe
  this behavior began with the recent ssh upgrade on woody.

  For example, if you run "ssh host date", you get your prompt back.
  However, if you run "ssh host xterm" and log out of the term, the
  xterm goes away, but you don't get your prompt back.

  It appears to be related to bug Bug #116888, and I've added this
  update to that bug. But I was hoping others might have some
  work arounds.

  Here's a script of ssh -v of the above commands. The message "Killed
  by signal 2." was generated when I typed C-c.

Script started on Thu Nov  8 09:53:54 2001
[SCRIPT:wohler@uluru:498]$ ssh -v gbr.newt.com xterm
OpenSSH_2.9p2, SSH protocols 1.5/2.0, OpenSSL 0x0090602f
debug1: Reading configuration data /home/wohler/.ssh/config
debug1: Applying options for *newt.com
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Seeding random number generator
debug1: Rhosts Authentication disabled, originating port will not be trusted.
debug1: restore_uid
debug1: ssh_connect: getuid 2142 geteuid 0 anon 1
debug1: Connecting to gbr.newt.com [209.233.16.176] port 22.
debug1: temporarily_use_uid: 2142/100 (e=0)
debug1: restore_uid
debug1: temporarily_use_uid: 2142/100 (e=0)
debug1: restore_uid
debug1: Connection established.
debug1: read PEM private key done: type DSA
debug1: read PEM private key done: type RSA
debug1: identity file /home/wohler/.ssh/identity type 0
debug1: identity file /home/wohler/.ssh/id_rsa type 1
debug1: identity file /home/wohler/.ssh/id_dsa type -1
debug1: Remote protocol version 1.99, remote software version OpenSSH_2.9p2
debug1: match: OpenSSH_2.9p2 pat ^OpenSSH
Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_2.9p2
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: dh_gen_key: priv key bits set: 125/256
debug1: bits set: 989/2049
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'gbr.newt.com' is known and matches the RSA host key.
debug1: Found key in /home/wohler/.ssh/known_hosts2:6
debug1: bits set: 1038/2049
debug1: ssh_rsa_verify: signature correct
debug1: kex_derive_keys
debug1: newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: waiting for SSH2_MSG_NEWKEYS
debug1: newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: done: ssh_kex2.
debug1: send SSH2_MSG_SERVICE_REQUEST
debug1: service_accept: ssh-userauth
debug1: got SSH2_MSG_SERVICE_ACCEPT
debug1: authentications that can continue: publickey,password,keyboard-interactive
debug1: next auth method to try is publickey
debug1: userauth_pubkey_agent: testing agent key /home/wohler/.ssh/id_rsa
debug1: input_userauth_pk_ok: pkalg ssh-rsa blen 149 lastkey 0x8091aa8 hint -1
debug1: ssh-userauth2 successful: method publickey
debug1: channel 0: new [client-session]
debug1: channel_new: 0
debug1: send channel open 0
debug1: Entering interactive session.
debug1: client_init id 0 arg 0
debug1: Requesting X11 forwarding with authentication spoofing.
debug1: Sending command: xterm
debug1: channel 0: open confirm rwindow 0 rmax 16384
debug1: client_input_channel_open: ctype x11 rchan 2 win 4096 max 2048
debug1: client_request_x11: request from 209.233.16.176 51955
debug1: fd 7 setting O_NONBLOCK
debug1: fd 7 IS O_NONBLOCK
debug1: channel 1: new [x11]
debug1: confirm x11
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug1: channel 0: rcvd eof
debug1: channel 0: output open -> drain
debug1: channel 0: rcvd close
debug1: channel 0: input open -> closed
debug1: channel 0: close_read
debug1: channel 1: rcvd eof
debug1: channel 1: output open -> drain
debug1: channel 0: obuf empty
debug1: channel 0: output drain -> closed
debug1: channel 0: close_write
debug1: channel 0: send close
debug1: channel 0: is dead
debug1: channel_free: channel 0: status: The following connections are open:
  #0 client-session (t4 r0 i8/0 o128/0 fd -1/-1)
  #1 x11 (t4 r2 i1/0 o32/0 fd 7/7)

debug1: channel_free: channel 0: dettaching channel user
debug1: channel 1: obuf empty
debug1: channel 1: output drain -> closed
debug1: channel 1: close_write
debug1: channel 1: read<=0 rfd 7 len 0
debug1: channel 1: read failed
debug1: channel 1: input open -> drain
debug1: channel 1: close_read
debug1: channel 1: input: no drain shortcut
debug1: channel 1: ibuf empty
debug1: channel 1: input drain -> closed
debug1: channel 1: send eof
debug1: channel 1: send close
debug1: channel 1: rcvd close
debug1: channel 1: is dead
debug1: channel_free: channel 1: status: The following connections are open:
  #1 x11 (t4 r2 i8/0 o128/0 fd 7/7)

Killed by signal 2.
debug1: Calling cleanup 0x805a5c4(0x0)
debug1: Calling cleanup 0x8062e7c(0x0)

[SCRIPT:wohler@uluru:499]$ ssh -v gbr.newt.com date
OpenSSH_2.9p2, SSH protocols 1.5/2.0, OpenSSL 0x0090602f
debug1: Reading configuration data /home/wohler/.ssh/config
debug1: Applying options for *newt.com
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Seeding random number generator
debug1: Rhosts Authentication disabled, originating port will not be trusted.
debug1: restore_uid
debug1: ssh_connect: getuid 2142 geteuid 0 anon 1
debug1: Connecting to gbr.newt.com [209.233.16.176] port 22.
debug1: temporarily_use_uid: 2142/100 (e=0)
debug1: restore_uid
debug1: temporarily_use_uid: 2142/100 (e=0)
debug1: restore_uid
debug1: Connection established.
debug1: read PEM private key done: type DSA
debug1: read PEM private key done: type RSA
debug1: identity file /home/wohler/.ssh/identity type 0
debug1: identity file /home/wohler/.ssh/id_rsa type 1
debug1: identity file /home/wohler/.ssh/id_dsa type -1
debug1: Remote protocol version 1.99, remote software version OpenSSH_2.9p2
debug1: match: OpenSSH_2.9p2 pat ^OpenSSH
Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_2.9p2
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-cbc hmac-md5 none
debug1: kex: client->server aes128-cbc hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: dh_gen_key: priv key bits set: 138/256
debug1: bits set: 978/2049
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'gbr.newt.com' is known and matches the RSA host key.
debug1: Found key in /home/wohler/.ssh/known_hosts2:6
debug1: bits set: 994/2049
debug1: ssh_rsa_verify: signature correct
debug1: kex_derive_keys
debug1: newkeys: mode 1
debug1: SSH2_MSG_NEWKEYS sent
debug1: waiting for SSH2_MSG_NEWKEYS
debug1: newkeys: mode 0
debug1: SSH2_MSG_NEWKEYS received
debug1: done: ssh_kex2.
debug1: send SSH2_MSG_SERVICE_REQUEST
debug1: service_accept: ssh-userauth
debug1: got SSH2_MSG_SERVICE_ACCEPT
debug1: authentications that can continue: publickey,password,keyboard-interactive
debug1: next auth method to try is publickey
debug1: userauth_pubkey_agent: testing agent key /home/wohler/.ssh/id_rsa
debug1: input_userauth_pk_ok: pkalg ssh-rsa blen 149 lastkey 0x8091a28 hint -1
debug1: ssh-userauth2 successful: method publickey
debug1: channel 0: new [client-session]
debug1: channel_new: 0
debug1: send channel open 0
debug1: Entering interactive session.
debug1: client_init id 0 arg 0
debug1: Requesting X11 forwarding with authentication spoofing.
debug1: Sending command: date
debug1: channel 0: open confirm rwindow 0 rmax 16384
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug1: channel 0: rcvd eof
debug1: channel 0: output open -> drain
debug1: channel 0: rcvd close
debug1: channel 0: input open -> closed
debug1: channel 0: close_read
Thu Nov  8 09:54:40 PST 2001
debug1: channel 0: obuf empty
debug1: channel 0: output drain -> closed
debug1: channel 0: close_write
debug1: channel 0: send close
debug1: channel 0: is dead
debug1: channel_free: channel 0: status: The following connections are open:
  #0 client-session (t4 r0 i8/0 o128/0 fd -1/-1)

debug1: channel_free: channel 0: dettaching channel user
debug1: Transferred: stdin 0, stdout 0, stderr 0 bytes in 0.2 seconds
debug1: Bytes per second: stdin 0.0, stdout 0.0, stderr 0.0
debug1: Exit status 0
[SCRIPT:wohler@uluru:500]$ exit

Script done on Thu Nov  8 09:54:58 2001
 
--
Bill Wohler <wohler@newt.com>  http://www.newt.com/wohler/  GnuPG ID:610BD9AD
Maintainer of comp.mail.mh FAQ and mh-e. Vote Libertarian!
If you're passed on the right, you're in the wrong lane.
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