[Icecast-dev] Segmentation fault issue with new install

Tue Apr 28 07:27:49 PDT 2015

Hi all,
see my reply inline.
Cheers, Jan-Pieter

2015-04-26 7:23 GMT+02:00 "Thomas B. Rücker" <thomas at ruecker.fi>:

> On 04/25/2015 07:32 PM, Jan-Pieter wrote:
> > Hi all,
> >
> > I am a long-time user of Icecast, always without problems. However i
> > made a new setup using icecast 2.4.1 on a fresh and quick CentOS VPS.
>
> EPEL package or from somewhere else?
>
> it's just a standard CentOS 6.6 release, no EPEL. Distri from hosting
provider. [root at h2429770 tmp]# uname -a
Linux h2429770.stratoserver.net 2.6.32-042stab103.6 #1 SMP Wed Jan 21
13:07:39 MSK 2015 x86_64 x86_64 x86_64 GNU/Linux

>
> > The issue is that starting icecast gives a segmentation fault at
> > around 80% of all starts. No core file nor a entry in error.log is
> posted.
>
> Enable core dumps using "ulimit -c unlimited". The PWD from where you
> start Icecast needs to be writeable.
>

Even with ulimit -c unlimited and running from a writable PWD no core is
dumped.

>
>
> > In the remaining 20% of the starts icecast start with no problem.
> >
> > Contents of the error.log with a succesfull start (20% of icecast
> starts):
> > [2015-04-25  21:08:40] INFO main/main Icecast 2.4.1 server started
> > [2015-04-25  21:08:40] INFO connection/get_ssl_certificate No SSL
> > capability
> > [2015-04-25  21:08:40] INFO stats/_stats_thread stats thread started
> > [2015-04-25  21:08:40] INFO yp/yp_update_thread YP update thread started
> > [2015-04-25  21:08:40] INFO source/source_fallback_file mountpoint
> > /geen-uitzending.mp3 is reserved
> > [2015-04-25  21:08:40] WARN format/format_get_type Unsupported or
> > legacy stream type: "audio/mpeg". Falling back to generic minimal
> > handler for best effort.
> > [2015-04-25  21:08:40] WARN source/source_fallback_file mountpoint
> > "/geen-uitzending.mp3" already reserved
> > [2015-04-25  21:08:40] INFO source/source_main listener count on
> > /geen-uitzending.mp3 now 0
> >
> >
> > Contents of error.log with a segmentation fault direct after start
> > (80% of icecast starts):
> > 2015-04-25  21:09:05] INFO main/main Icecast 2.4.1 server started
> > [2015-04-25  21:09:05] INFO connection/get_ssl_certificate No SSL
> > capability
> > [2015-04-25  21:09:05] INFO yp/yp_update_thread YP update thread started
> > [2015-04-25  21:09:05] INFO source/source_fallback_file mountpoint
> > /geen-uitzending.mp3 is reserved
> > [2015-04-25  21:09:05] WARN format/format_get_type Unsupported or
> > legacy stream type: "audio/mpeg". Falling back to generic minimal
> > handler for best effort.
> > [2015-04-25  21:09:05] INFO stats/_stats_thread stats thread started
>
> Can you attach your icecast.xml please (with passwords removed)?
> This might help reproduce the problem.
>
>
I attached icecast.xml. I also turned debug errorlog level on.
Results with debug on:

good start:
[2015-04-28  15:56:39] INFO main/main Icecast 2.4.1 server started
[2015-04-28  15:56:39] DBUG yp/yp_recheck_config Updating YP configuration
[2015-04-28  15:56:39] INFO connection/get_ssl_certificate No SSL capability
[2015-04-28  15:56:39] INFO stats/_stats_thread stats thread started
[2015-04-28  15:56:39] INFO yp/yp_update_thread YP update thread started
[2015-04-28  15:56:39] INFO source/source_fallback_file mountpoint
/geen-uitzending.mp3 is reserved
[2015-04-28  15:56:39] DBUG connection/connection_complete_source sources
count is 0
[2015-04-28  15:56:39] WARN format/format_get_type Unsupported or legacy
stream type: "audio/mpeg". Falling back to generic minimal handler for best
effort.
[2015-04-28  15:56:39] DBUG connection/connection_complete_source source is
ready to start
[2015-04-28  15:56:39] DBUG source/source_init Source creation complete
[2015-04-28  15:56:39] WARN source/source_fallback_file mountpoint
"/geen-uitzending.mp3" already reserved
[2015-04-28  15:56:39] INFO source/source_main listener count on
/geen-uitzending.mp3 now 0
[2015-04-28  15:56:39] DBUG stats/modify_node_event update global sources
(1)
[2015-04-28  15:56:39] DBUG stats/process_source_event new source stat
/geen-uitzending.mp3
[2015-04-28  15:56:39] DBUG stats/modify_node_event update global
source_client_connections (1)
[2015-04-28  15:56:39] DBUG stats/process_source_event new node listeners
(0)
[2015-04-28  15:56:39] DBUG stats/process_source_event new node listenurl (
http://stream3.server7.nl:80/geen-uitzending.mp3)
[2015-04-28  15:56:39] DBUG stats/modify_node_event update global
source_total_connections (1)
[2015-04-28  15:56:39] DBUG stats/process_source_event new node
slow_listeners (0)
[2015-04-28  15:56:39] DBUG stats/modify_node_event update
"/geen-uitzending.mp3" listeners (0)
[2015-04-28  15:56:39] DBUG stats/process_source_event new node
listener_peak (0)
[2015-04-28  15:56:39] DBUG stats/process_source_event new node
stream_start (Tue, 28 Apr 2015 15:56:39 +0200)
[2015-04-28  15:56:39] DBUG stats/process_source_event new node
stream_start_iso8601 (2015-04-28T15:56:39+0200)
[2015-04-28  15:56:39] DBUG stats/process_source_event new node
total_bytes_read (0)
[2015-04-28  15:56:39] DBUG stats/process_source_event new node
total_bytes_sent (0)
[2015-04-28  15:56:39] DBUG stats/modify_node_event update
"/geen-uitzending.mp3" listeners (0)
[2015-04-28  15:56:40] DBUG slave/_slave_thread checking master stream list

bad start (segfault):
[2015-04-28  15:56:53] INFO main/main Icecast 2.4.1 server started
[2015-04-28  15:56:53] DBUG yp/yp_recheck_config Updating YP configuration
[2015-04-28  15:56:53] INFO connection/get_ssl_certificate No SSL capability
[2015-04-28  15:56:53] INFO yp/yp_update_thread YP update thread started
[2015-04-28  15:56:53] INFO source/source_fallback_file mountpoint
/geen-uitzending.mp3 is reserved
[2015-04-28  15:56:53] DBUG connection/connection_complete_source sources
count is 0
[2015-04-28  15:56:53] WARN format/format_get_type Unsupported or legacy
stream type: "audio/mpeg". Falling back to generic minimal handler for best
effort.
[2015-04-28  15:56:53] DBUG connection/connection_complete_source source is
ready to start
[2015-04-28  15:56:53] DBUG source/source_init Source creation complete
[2015-04-28  15:56:53] INFO stats/_stats_thread stats thread started
[2015-04-28  15:56:53] DBUG stats/process_source_event new source stat
/geen-uitzending.mp3

>
> > Both the stream and the fallback file are .mp3 type. I tried removing
> > the fallback entry. Then icecast starts always normally. So it seems
> > related to the .mp3 fallback.
> >
> > Also I tried to launch icecast with strace, and this NEVER fails. No
> > segmentation faults!
> >
> >
> > Any idea what's going wrong? Something going wrong with timing on a
> > fast server?
>
> It sounds like you've found a race condition. I'm not exactly sure
> what's happening though.
> By the log output something seems to be instantly accessing the stream.
> Notice the order of the stats_thread is different in both.
>
>
Yes this is the only interesting thing. The segfault only happens when
"INFO stats/_stats_thread stats thread started"
is missing in the error.log. So with every succesful start this line gets
logged, and if the line is missing the segfault occurs.

I also tried running using valgrind on advice of Philipp, but when running
with valgrind the segfault does not occur and icecast starts normally...
(same as with gdb)

>
> Cheers
>
> Thomas
>
>
>
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