So far it happened two (2) times, last time yesterday. Opened case with Asterisk https://issues.asterisk.org/jira/browse/ASTERISK-24593

All FXO channels went off-hook, Operator FXS was constantly ringing. If I picked a handset there was a dead silence. If I put it back on hook it would start ringing.

FreePBX interface would not operate properly. Specifically it was slow to authenticate, then some irrelevant messages were presented in the upper left corner of the browser tab.

I tried to execute “core stop now” on the console and it would just hang.

I was able to stop the Asterisk by connecting from another session and executing “core stop now” the second time.

After the restart everything was back to normal.

Technical details.

/var/log/asterisk/full shows a number of messages like the following:
[2014-12-03 13:24:29] WARNING[31947] channel.c: Exceptionally long voice queue length queuing to Local/414@from-internal-00000165;1
[2014-12-03 13:24:30] WARNING[31947] channel.c: Exceptionally long voice queue length queuing to Local/414@from-internal-00000165;1
[2014-12-03 13:24:31] WARNING[31947] channel.c: Exceptionally long voice queue length queuing to Local/414@from-internal-00000165;1
[2014-12-03 13:24:33] WARNING[31947] channel.c: Exceptionally long voice queue length queuing to Local/414@from-internal-00000165;1

/var/log/messages shows a huge number of messages similar to the below at about an hour and a half before Asterisk finally hang up:

Dec 3 12:30:14 pbx kernel: wctdm24xxp 0000:02:0c.0: Setting FXS hook state to 2 (04) framecount33123791
Dec 3 12:30:14 pbx kernel: wctdm24xxp 0000:02:0c.0: SLIC_LF OK: card=3 shadowd lasttxhook framecount33123797
Dec 3 12:30:16 pbx kernel: wctdm24xxp 0000:02:0c.0: Setting FXS hook state to 1 (06) framecount33125791
Dec 3 12:30:16 pbx kernel: wctdm24xxp 0000:02:0c.0: SLIC_LF OK: card=3 shadowF lasttxhook framecount33125797
Dec 3 12:30:20 pbx kernel: wctdm24xxp 0000:02:0c.0: Setting FXS hook state to 2 (04) framecount33129791
Dec 3 12:30:20 pbx kernel: wctdm24xxp 0000:02:0c.0: SLIC_LF OK: card=3 shadowd lasttxhook framecount33129797
Dec 3 12:30:22 pbx kernel: wctdm24xxp 0000:02:0c.0: Setting FXS hook state to 1 (06) framecount33131791
Dec 3 12:30:22 pbx kernel: wctdm24xxp 0000:02:0c.0: SLIC_LF OK: card=3 shadowF lasttxhook framecount33131797
Dec 3 12:30:26 pbx kernel: wctdm24xxp 0000:02:0c.0: Setting FXS hook state to 2 (04) framecount33135791
Dec 3 12:30:26 pbx kernel: wctdm24xxp 0000:02:0c.0: SLIC_LF OK: card=3 shadowd lasttxhook framecount33135797
Dec 3 12:30:28 pbx kernel: wctdm24xxp 0000:02:0c.0: Setting FXS hook state to 1 (06) framecount33137791
Dec 3 12:30:28 pbx kernel: wctdm24xxp 0000:02:0c.0: SLIC_LF OK: card=3 shadowF lasttxhook framecount33137797
Dec 3 12:30:32 pbx kernel: wctdm24xxp 0000:02:0c.0: Setting FXS hook state to 2 (04) framecount33141791
Dec 3 12:30:32 pbx kernel: wctdm24xxp 0000:02:0c.0: SLIC_LF OK: card=3 shadowd lasttxhook framecount33141797
Dec 3 12:30:34 pbx kernel: wctdm24xxp 0000:02:0c.0: Setting FXS hook state to 1 (06) framecount33143791
Dec 3 12:30:34 pbx kernel: wctdm24xxp 0000:02:0c.0: SLIC_LF OK: card=3 shadowF lasttxhook framecount33143797
Dec 3 12:30:38 pbx kernel: wctdm24xxp 0000:02:0c.0: Setting FXS hook state to 2 (04) framecount33147791
Dec 3 12:30:38 pbx kernel: wctdm24xxp 0000:02:0c.0: SLIC_LF OK: card=3 shadowd lasttxhook framecount33147797
Dec 3 12:30:40 pbx kernel: wctdm24xxp 0000:02:0c.0: Setting FXS hook state to 1 (06) framecount33149791
Dec 3 12:30:40 pbx kernel: wctdm24xxp 0000:02:0c.0: SLIC_LF OK: card=3 shadowF lasttxhook framecount33149797
Dec 3 12:30:44 pbx kernel: wctdm24xxp 0000:02:0c.0: Setting FXS hook state to 2 (04) framecount33153791
Dec 3 12:30:44 pbx kernel: wctdm24xxp 0000:02:0c.0: SLIC_LF OK: card=3 shadowd lasttxhook framecount33153797

No core dump was produced.