[tor-bugs] #23915 [Applications/Tor Browser Sandbox]: 7.0.7 and later fails to work without `SECCOMP_FILTER_FLAG_TSYNC`.

[Tor Bug Tracker & Wiki]

#23915: 7.0.7 and later fails to work without `SECCOMP_FILTER_FLAG_TSYNC`.
--------------------------------------------------+---------------------
     Reporter:  yawning                           |      Owner:  yawning
         Type:  defect                            |     Status:  new
     Priority:  Medium                            |  Milestone:
    Component:  Applications/Tor Browser Sandbox  |    Version:
     Severity:  Normal                            |   Keywords:
Actual Points:                                    |  Parent ID:
       Points:                                    |   Reviewer:
      Sponsor:                                    |
--------------------------------------------------+---------------------
 {{{
 2017/10/20 03:16:42 firefox: Sandbox: opendir /proc/self/task: No such
 file or directory
 2017/10/20 03:16:42 firefox: [Parent 3] WARNING: pipe error (59):
 Connection reset by peer: file /home/debian/build/tor-
 browser/ipc/chromium/src/chrome/common/ipc_channel_posix.cc, line 322
 2017/10/20 03:16:42 firefox: [Parent 3] WARNING: pipe error (57):
 Connection reset by peer: file /home/debian/build/tor-
 browser/ipc/chromium/src/chrome/common/ipc_channel_posix.cc, line 322
 2017/10/20 03:16:42 firefox: ###!!! [Parent][RunMessage] Error: Channel
 error: cannot send/recv
 2017/10/20 03:16:42 firefox: ###!!! [Parent][MessageChannel] Error:
 (msgtype=0x2C0086,name=PBrowser::Msg_Destroy) Channel error: cannot
 send/recv
 }}}

 This only affects systems running kernels that pre-date 3.17, which
 annoyingly enough currently includes Debian oldstable.  It's an artifact
 of "the sandbox doesn't mount `/proc`", and "firefox wants to use
 `/proc/self/task` to see if a process has threads or not".  The need for
 the latter goes away with the `seccomp()` flag, which is why I never saw
 the issue.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/23915>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online