mount failed to process probably corrupted CD

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http://unix.stackexchange.com – I wanted to check a CD from my drawer. I inserted it into my drive and issued mount. I got mount: block device /dev/sr0 is write-protected, mounting read-only mount command did not exit. I checked its state in top: 4640 root 20 0 27088 1280 1060 R 99,8 0,0 1:36.90 mount 99,8% CPU usage what was not true because usage of all my cores is almost 0,0%. I tried to kill it - no success (both signals KILL and TERM fail to stop the mount programme). I tried reboot -f and reboot got into D state. fuser helped neither. /dev/sr0 is my cdrom and it was not present in mount output umoun (HowTos)