[Bug 1306877] Re: sshd stops accepting new connections after configuration reload

[Launchpad Bug Tracker]

This bug was fixed in the package openssh - 1:6.6p1-2ubuntu1

---------------
openssh (1:6.6p1-2ubuntu1) trusty; urgency=medium

  * Upload from Debian git repository to fix a release-critical bug.
  * Debconf translations:
    - French (thanks, Étienne Gilli; closes: #743242).
  * Never signal the service supervisor with SIGSTOP more than once, to
    prevent a hang on re-exec (thanks, Robie Basak; LP: #1306877).
 -- Colin Watson <cjwatson at ubuntu.com>   Mon, 14 Apr 2014 12:20:48 +0100

** Changed in: openssh (Ubuntu)
       Status: Fix Committed => Fix Released

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https://bugs.launchpad.net/bugs/1306877

Title:
  sshd stops accepting new connections after configuration reload

Status in “openssh” package in Ubuntu:
  Fix Released

Bug description:
  When upstart is enabled, sshd stops accepting new connections after
  reloading configuration by "initctl reload ssh".

  It looks like sshd is frozen with SIGSTOP after receiving SIGHUP.

  [nya at sora ~]% ps auxww | grep sshd
  root     10557  0.0  0.1  61364  3056 ?        Ss   13:46   0:00 /usr/sbin/sshd -D
  [nya at sora ~]% sudo strace -p 10557
  Process 10557 attached
  select(7, [3 4], NULL, NULL, NULL^CProcess 10557 detached
   <detached ...>
  [nya at sora ~]% sudo reload ssh
  [nya at sora ~]% sudo strace -p 10557
  Process 10557 attached
  --- stopped by SIGSTOP ---

  I guess it's caused by a Debian-specific patch:
  debian/patches/sigstop.patch. The patch makes sshd STOP when it's
  ready to start and have upstart resume it by specifying "expect stop"
  in /etc/init/ssh.conf. On receiving SIGHUP sshd re-executes itself and
  STOPs again, but upstart does not perform resume.

  Reproduced under Ubuntu 14.04 Trusty
  Package version: openssh 1:6.6p1-2

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