Re: [monit] Can't restart monit

[Martin Pala]

On Jan 21, 2009, at 1:27 PM, Nicola Tiling wrote:

> Am 20.01.2009 um 22:27 schrieb Martin Pala:
>
> > The root cause most probably is, that monit masks signals  
> > (including SIGTERM) for critical sections. Freebsd's /etc/rc.subr  
> > routines which are used by monit's rc script performs the restart  
> > by stopping and starting the process. The stop is performed by  
> > sending SIGTERM to the process. When Monit is in critical section,  
> > it can thus ignore the SIGTERM signal whereas the rc script thinks  
> > that it managed to signalize process to stop and will wait for pid  
> > to exit.
>
>
> I think monit freezes. Today the last entry in /var/log/monit is  
> from [ Jan 21 03:26:04]  and mmonit says "No report from monit. Last  
> report was Wed, 21 Jan 2009 03:24:03". The webconsole of monit  
> itself is reachable, but no watched processes are clickable.


If it will happen again (with fixed version), please can you get  
thread stacktraces using?:

  gdb monit <monit's pid>


Example (monit running with pid 941):

# gdb /usr/local/bin/monit 941

(gdb) info threads
  2 process 941 thread 0x903  0x96fcb6f2 in select$DARWIN_EXTSN ()
* 1 process 941 thread 0x203  0x96f833ae in __semwait_signal ()

(gdb) thr 1
[Switching to thread 1 (process 941 thread 0x203)]
0x96f833ae in __semwait_signal ()

(gdb) bt
#0  0x96f833ae in __semwait_signal ()
#1  0x96f8322f in nanosleep$UNIX2003 ()
#2  0x96fd8e71 in sleep$UNIX2003 ()
#3  0x00009ade in main (argc=3, argv=0xbffffd18) at monitor.c:503

(gdb) thr 2
[Switching to thread 2 (process 941 thread 0x903)]
0x96fcb6f2 in select$DARWIN_EXTSN ()

(gdb) bt
#0  0x96fcb6f2 in select$DARWIN_EXTSN ()
#1  0x0000a25c in can_read (socket=3, timeout=0) at net.c:487
#2  0x0002183d in socket_producer [inlined] () at http/engine.c:637
#3  0x0002183d in start_httpd (port=2812, backlog=0, bindAddr=0x0) at  
http/engine.c:207
#4  0x00007596 in thread_wrapper (arg=0x0) at http.c:177
#5  0x96fad095 in _pthread_start ()
#6  0x96facf52 in thread_start ()


Thanks,
Martin