[Varnish] #928: strace attached to child causes child to die

[Varnish]

#928: strace attached to child causes child to die
------------------------------+---------------------------------------------
 Reporter:  David Busby       |        Type:  defect  
   Status:  new               |    Priority:  normal  
Milestone:                    |   Component:  varnishd
  Version:  2.1.5             |    Severity:  normal  
 Keywords:  strace,child,die  |  
------------------------------+---------------------------------------------
 Attempted strace

 {{{
 strace -p 8671
 Process 8671 attached - interrupt to quit
 close(6)                                = 0
 close(7)                                = 0
 write(1, "Child dies", 10)              = 10
 write(1, "\n", 1)                       = 1
 exit_group(1)                           = ?
 Process 8671 detached
 }}}

 Output to /var/log/messages


 {{{
 May 31 14:37:29 109 live[8670]: Child (8671) said Child dies
 May 31 14:37:30 109 live[8670]: Child (8671) died
 May 31 14:37:30 109 live[8670]: child (9235) Started
 May 31 14:37:30 109 live[8670]: Child (9235) said
 May 31 14:37:30 109 live[8670]: Child (9235) said Child starts
 May 31 14:37:30 109 live[8670]: Child (9235) said Probe("GET /status.html
 HTTP/1.1
 May 31 14:37:30 109 live[8670]: Child (9235) said
 May 31 14:37:30 109 live[8670]: Child (9235) said Host: 127.0.0.1
 May 31 14:37:30 109 live[8670]: Child (9235) said
 May 31 14:37:30 109 live[8670]: Child (9235) said Connection: close
 May 31 14:37:30 109 live[8670]: Child (9235) said
 May 31 14:37:30 109 last message repeated 2 times
 May 31 14:37:30 109 live[8670]: Child (9235) said ", 0.05, 2)
 May 31 14:37:30 109 live[8670]: Child (9235) said Probe("GET /status.html
 HTTP/1.1
 May 31 14:37:30 109 live[8670]: Child (9235) said
 May 31 14:37:30 109 live[8670]: Child (9235) said Host: 172.31.56.23
 May 31 14:37:30 109 live[8670]: Child (9235) said
 May 31 14:37:30 109 live[8670]: Child (9235) said Connection: close
 May 31 14:37:30 109 live[8670]: Child (9235) said
 May 31 14:37:30 109 last message repeated 2 times
 May 31 14:37:30 109 live[8670]: Child (9235) said ", 0.05, 2)
 }}}

 This is hindering diagnostics of a "http first read error: -1 11 (Resource
 temporarily unavailable)"

 this "Child dies" seems to occur regardless of the VCL being run.

 Please let me know if more information is required.

 Regards

 D.Busby

-- 
Ticket URL: <http://varnish-cache.org/trac/ticket/928>
Varnish <http://varnish-cache.org/>
The Varnish HTTP Accelerator