Re: 1.7.2: ssh -X unresponsive until xauth PPID killed
On 27/03/2010 21:53, Mark McConnell wrote: (Please forgive the repost - this version has the attachments mentioned) After installing Cygwin 1.7.2 for the first time on Windows Server 2008 SP2, I discovered that I could not connect to a remote host using Cygwin's ssh, if X is forwarded. ssh -X host or ssh -Y host : program becomes unresponsive. I've attached the output of cygcheck -s -v -r to this message, and /var/log/XWin.0.log. I should mention as an aside that there are other clues that my Cygwin installation is flawed (a local gvim gui will not display, man dumps core). Given that, I'm thinking that the problem you describe with the xauth subprocess is probably symptomatic of some deeper problem with you installation or environment. You should probably ask for help on the main cygwin list. Below, I describe two experiments that indicate that my X forwarding problem is somehow related to xauth* and its PPID: ### 'ssh -X host gui' displays if the PPID of xauth* is killed ### First, I open a new mintty window within the Cygwin environment and issue the command to start gvim on the remote server, using the forwarded X display. No gui is displayed. The cursor returns below the prompt. ^d or ^c do not terminate the process ( however, I can suspend it from that window by typing ^z, and I can return it to the foreground with fgjob ). -- Jon TURNEY Volunteer Cygwin/X X Server maintainer -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://x.cygwin.com/docs/ FAQ: http://x.cygwin.com/docs/faq/
Re: 1.7.2: ssh -X unresponsive until xauth PPID killed
2010/3/29 Jon TURNEY jon.tur...@dronecode.org.uk: On 27/03/2010 21:53, Mark McConnell wrote: (Please forgive the repost - this version has the attachments mentioned) After installing Cygwin 1.7.2 for the first time on Windows Server 2008 SP2, I discovered that I could not connect to a remote host using Cygwin's ssh, if X is forwarded. ssh -X host or ssh -Y host : program becomes unresponsive. I've attached the output of cygcheck -s -v -r to this message, and /var/log/XWin.0.log. I should mention as an aside that there are other clues that my Cygwin installation is flawed (a local gvim gui will not display, man dumps core). Given that, I'm thinking that the problem you describe with the xauth subprocess is probably symptomatic of some deeper problem with you installation or environment. You should probably ask for help on the main cygwin list. Below, I describe two experiments that indicate that my X forwarding problem is somehow related to xauth* and its PPID: ### 'ssh -X host gui' displays if the PPID of xauth* is killed ### First, I open a new mintty window within the Cygwin environment and issue the command to start gvim on the remote server, using the forwarded X display. No gui is displayed. The cursor returns below the prompt. ^d or ^c do not terminate the process ( however, I can suspend it from that window by typing ^z, and I can return it to the foreground with fgjob ). -- Jon TURNEY Volunteer Cygwin/X X Server maintainer Thank you, Jon. I'll give some thought to how to summarize the various problems I'm experiencing and send that to the main list. Mark -- -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://x.cygwin.com/docs/ FAQ: http://x.cygwin.com/docs/faq/
Re: 1.7.2: ssh -X unresponsive until xauth PPID killed
I turned off Data Execution Protection for all except crucial Windows programs, and the XWin problems I described were resolved. Thanks for your patience, Mark -- -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://x.cygwin.com/docs/ FAQ: http://x.cygwin.com/docs/faq/
Re: 1.7.2: ssh -X unresponsive until xauth PPID killed
2010/3/29 Mark McConnell markd.mcconn...@gmail.com: I turned off Data Execution Protection for all except crucial Windows programs, and the XWin problems I described were resolved. Thanks for your patience, Mark -- I discovered afterward that this is related to FAQ #14. This Server 2008 is running Terminal Services, and that is the key fact. http://www.cygwin.com/faq/faq.setup.html#faq.setup.setup-fails-on-ts I'm sorry that faq escaped my attention. I didn't recognize the connection, since I set up Cygwin on a local console, not through Terminal Services; but now the relationship is obvious to me. Mark -- -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://x.cygwin.com/docs/ FAQ: http://x.cygwin.com/docs/faq/
1.7.2: ssh -X unresponsive until xauth PPID killed
After installing Cygwin 1.7.2 for the first time on Windows Server 2008 SP2, I discovered that I could not connect to a remote host using Cygwin's ssh, if X is forwarded. ssh -X host or ssh -Y host : program becomes unresponsive. I've attached the output of cygcheck -s -v -r to this message, and /var/log/XWin.0.log. I should mention as an aside that there are other clues that my Cygwin installation is flawed (a local gvim gui will not display, man dumps core). Below, I describe two experiments that indicate that my X forwarding problem is somehow related to xauth* and its PPID: ### 'ssh -X host gui' displays if the PPID of xauth* is killed ### First, I open a new mintty window within the Cygwin environment and issue the command to start gvim on the remote server, using the forwarded X display. No gui is displayed. The cursor returns below the prompt. ^d or ^c do not terminate the process ( however, I can suspend it from that window by typing ^z, and I can return it to the foreground with fg job ). pt0 $ ssh -X dasftp gvim | I open a second mintty instance and look at the process running locally: pt1 $ ps PIDPPIDPGID WINPID TTY UIDSTIME COMMAND 4532 14532 5296 con 11137 11:40:42 /usr/bin/XWin 343245323432 4244? 11137 13:15:21 /usr/bin/mintty 336434323364 36880 11137 13:15:21 /usr/bin/bash 597233645972 24360 11137 13:15:39 /usr/bin/ssh 579259725972 57920 11137 13:15:39 /usr/bin/sh 263257925972 25480 11137 13:15:39 /usr/bin/xauth In the second terminal I kill the sh* process that is the parent of xauth*. The remote gvim gui immediately appears. xauth* is now running with PPID 1 pt1 $ ps | grep /usr/bin/sh | sed -e 's/^\s*//' | kill `sed -e 's/\s.*//'` ; ps PIDPPIDPGID WINPID TTY UIDSTIME COMMAND 4532 14532 5296 con 11137 11:40:42 /usr/bin/XWin 343245323432 4244? 11137 13:15:21 /usr/bin/mintty 336434323364 36880 11137 13:15:21 /usr/bin/bash 597233645972 24360 11137 13:15:39 /usr/bin/ssh 2632 15972 25480 11137 13:15:39 /usr/bin/xauth After closing gvim, I take a peek at the processes left behind. ssh* has terminated, bash* has been idle, xauth* continues to run even if X is closed. Its PPID has changed to 1 pt1 $ ps PIDPPIDPGID WINPID TTY UIDSTIME COMMAND 4532 14532 5296 con 11137 11:40:42 /usr/bin/XWin 343245323432 4244? 11137 13:15:21 /usr/bin/mintty I336434323364 36880 11137 13:15:21 /usr/bin/bash 2632 15972 25480 11137 13:15:39 /usr/bin/xauth pt1 $ kill 2632 bash: kill: (2632) - Resource temporarily unavailable Summarizing: SSH authentication succeeds but the ssh* is unresponsive when started with X forwarding. Killing the PPID of xauth* leaves it running in the background. xauth* will remain running even after the X server is closed. To kill the zombie xauth* I use Windows Task Manager. ## 'ssh -X host' succeeds after PPID of xauth* is killed ## Here's a simplified version of the experiment. In terminal 1: pt0 $ ssh -v -v -X dasftp 2 ssh.out In terminal 2, I kill the PPID of xauth* (/usr/bin/sh): pt1 $ ps | grep /usr/bin/sh | sed -e 's/^\s*//' | kill `sed -e 's/\s.*//'` ; In terminal 1 (connected to 'host'): Welcome to dasftp pt3 $ I have attached ssh.out also, which is the debug output of ssh -v -v -X host. I can provide a much more detailed description of the steps I've followed, if that would be helpful. Many thanks, Mark -- -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://x.cygwin.com/docs/ FAQ: http://x.cygwin.com/docs/faq/
