ssh-agent doesn't die

Fri Sep 27 00:34:00 GMT 2019

Hi,
I have noticed a (new?) problem with using ssh-agent to start a session, 
eg. with
 Â  ssh-agent xterm &
When the xterm (or whatever) command completes, the ssh-agent process is 
still left running in the background. It should stop once its subprocess 
is done.
As a simple test example, consider:
/bin/ssh-agent /bin/sleep 10
While the sleep is still running, ps shows:
 Â Â Â Â Â  PIDÂ Â Â  PPIDÂ Â Â  PGIDÂ Â Â Â  WINPIDÂ Â  TTYÂ Â Â Â Â Â Â Â  UIDÂ Â Â  STIME COMMAND
 Â Â Â Â  1694Â Â Â  1693Â Â Â  1694Â Â Â Â Â Â  1576Â  ?Â Â Â Â Â Â Â Â Â  22534 00:01:10 
/usr/bin/ssh-agent
 Â Â Â Â  1653Â Â Â Â Â Â  1Â Â Â  1653Â Â Â Â Â  11740Â  cons1Â Â Â Â Â  22534 00:00:37 
/usr/bin/bash
 Â Â Â Â  1693Â Â Â  1653Â Â Â  1693Â Â Â Â Â Â  1552Â  cons1Â Â Â Â Â  22534 00:01:10 
/usr/bin/sleep
One oddity is that ssh-agent is listed as a subprocess of sleep, not the 
other way round. pstree shows this clearly:
?-+-bash---pstree
 Â  `-bash---sleep---ssh-agent
Once the sleep finishes, ps shows:
 Â Â Â Â Â  PIDÂ Â Â  PPIDÂ Â Â  PGIDÂ Â Â Â  WINPIDÂ Â  TTYÂ Â Â Â Â Â Â Â  UIDÂ Â Â  STIME COMMAND
 Â Â Â Â  1694Â Â Â  1693Â Â Â  1694Â Â Â Â Â Â  1576Â  ?Â Â Â Â Â Â Â Â Â  22534 00:01:10 
/usr/bin/ssh-agent
 Â Â Â Â  1653Â Â Â Â Â Â  1Â Â Â  1653Â Â Â Â Â  11740Â  cons1Â Â Â Â Â  22534 00:00:37 
/usr/bin/bash
ie. ssh-agent is still running, though its PPID no longer exists.
I'm using the latest release versions of cygwin and openssh:
Cygwin Package Information
PackageÂ Â Â Â Â Â Â Â Â Â Â Â Â  VersionÂ Â Â Â Â Â Â  Status
cygwinÂ Â Â Â Â Â Â Â Â Â Â Â Â Â  3.0.7-1Â Â Â Â Â Â Â  OK
opensshÂ Â Â Â Â Â Â Â Â Â Â Â Â  8.0p1-2Â Â Â Â Â Â Â  OK
with Windows 10 1803 (2019-09 update). I use Sophos AV 10.8 with HitmanPro.
Previously, I haven't had this problem: ssh-agent stopped when it's 
subprocess stopped. I updated from Cygwin 2.10-1 (and contemporaneous 
openssh) fairly recently, and it's possible the problem started then. Or 
it could have been a Windows minor update, AV update, or some other 
setting change I made. Sorry I couldn't pin it down further.
Is it just me that sees this, or could it be a bug in ssh-agent or Cygwin?
If it is just me, my first suspicion would be HitmanPro, which 
previously caused silent failures with an earlier version of Cygwin (I 
reported in cygwin-patches@cygwin.com, June 2018). That bug is fixed, 
but maybe this is something new. If we can rule out a more general 
Cygwin bug, I can ask my IT support to try disabling the HitmanPro to test.
Thanks,
Tim.
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