dist-upgrade problem

debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable
(Reading database ... 31787 files and directories currently installed.)
Preparing to replace mysql-server-5.5 5.5.38-0+wheezy1 (using .../mysql-server-5.5_5.5.38-0+wheezy1_amd64.deb) ...
debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable
dpkg: error processing /var/cache/apt/archives/mysql-server-5.5_5.5.38-0+wheezy1_amd64.deb (--unpack):
 subprocess new pre-installation script returned error exit status 1
configured to not write apport reports
                                      debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable
dpkg: error while cleaning up:
 subprocess new post-removal script returned error exit status 1
Errors were encountered while processing:
 /var/cache/apt/archives/mysql-server-5.5_5.5.38-0+wheezy1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)