So the subject.
In the proccesses Asterisk is still present.
In console no messages at all.
SIP clients lose ability to register.
Impossible to make outgouing calls, and impossible to receive incoming calls.
In logs / var/log/asterisk/full there are a lot of strings like that:
audiohook.c: Read factory 0xb48aaf0 and write factory 0xb48b528 both fail to provide 160 samples
Asterisk starts working normally only after system command
service asterisk restart