Bug 1010

Summary:

SSH sometimes hangs on exit when multiple forwarded X11 clients are closed

Product:

Portable OpenSSH

Reporter:

Tomas Mraz <t8m>

Component:

sshd

Assignee:

OpenSSH Bugzilla mailing list <openssh-bugs>

Status:

CLOSED WORKSFORME

Severity:

normal

CC:

djm

Priority:

Version:

4.0p1

Hardware:

All

OS:

Linux

Attachments:

Description	Flags
Proposed patch	none

Description Tomas Mraz 2005-04-06 06:38:47 AEST

SSH sometimes hangs on exit when multiple forwarded X11 clients are closed.

This is not easy to reproduce however here are the steps which make it to
reproduce almost 100% for me:

1. ssh -Y host
2. xsm ; exit    in the ssh session
3. for i in `seq 1 50` ; do (nice -20 xterm &) ; done     in the xterm which was
started from xsm
4. after all the xterms are up and running shutdown immediately the xsm

Expected result:
ssh session ended normally

What really happens:
ssh session hangs

After looking at the debug log from the sshd it seems that some of the X11
channels are stuck waiting for output drain however it won't happen as the other
end - the xterm - already exited.

Comment 1 Tomas Mraz 2005-04-06 06:41:59 AEST

Created attachment 868 [details]
Proposed patch

This patch solves the problem for me however I'm not sure if it's completely
correct.

Comment 2 Damien Miller 2008-06-13 13:42:57 AEST

I can't replicate this with -current. Could you please try a snapshot to see if you can replicate the bug?

Comment 3 Tomas Mraz 2008-06-13 18:59:07 AEST

I cannot reproduce the problem anymore although I am not 100% sure it was fixed. I am now running completely different HW setup (more powerfull of course) so the race might not happen on it anymore, also the kernel is now 2.6.24... instead of 2.6.9 so that might also affect the race.
But let's close it worksforme, I can reopen it later if it appears again.

Comment 4 Damien Miller 2008-07-22 12:07:21 AEST

Mass update RESOLVED->CLOSED after release of openssh-5.1