Asterisk & dahdi freeze


I have problem with asterisk and dahdi - time to time it “freeze” - in log file there is information:

[Dec 22 14:38:43] ERROR[19539] chan_dahdi.c: PRI Span: 5 Trying to queue MDL-ERROR (F) when MDL-ERROR (F) is already scheduled

asterisk is working, but when i try to execute “core show channels” it shows only header of information:

Connected to Asterisk currently running on ZDAP (pid = 19506)
ZDAPCLI> core show channels
Channel Location State Application(Data)
CLI> core stop now
ZDAP*CLI> exit

asterisk also do not respond to “core stop now” - only “killall -9 asterisk” can stop it. What could be a problem?

You have a deadlock. You need to compile with the no optimise and thread debugging options (there is a small performance penalty for the first and a moderate one for the second). When it stall, you need to start a new console session and and rune “core show locks”, then get a backtrace using gdb (Google for “asterisk wiki backtrace” for more details.

Once you have this information, you should be in a position to raise a bug report on Please note, there is no guarantee that a fix will be found quickly.

Also note that, whilst there may be a bug in dahdi which is a co-factor, Asterisk shouldn’t deadlock, so the initial report needs to be against Asterisk.