ORA-15020: discovered duplicate ASM disk

INFO: Command /u01/app/grid/product/11.2.0/grid/bin/asmca -silent -oui_internal -configureASM -diskString /dev/oracleasm/disks -diskGroupName CRS -diskList /dev/oracleasm/disks/CRSVOL1,/dev/oracleasm/disks/CRSVOL2,/dev/oracleasm/disks/CRSVOL3 -redundancy EXTERNAL
INFO: ... GenericInternalPlugIn.handleProcess() entered.
INFO: ... GenericInternalPlugIn: getting configAssistantParmas.
INFO: ... GenericInternalPlugIn: checking secretArguments.
INFO: ... GenericInternalPlugIn: starting read loop.
INFO: Read: SYS_PASSWORD_PROMPT
INFO: Processing: SYS_PASSWORD_PROMPT for argument tag -sysAsmPassword
INFO: Read: ASMSNMP_PASSWORD_PROMPT
INFO: Processing: ASMSNMP_PASSWORD_PROMPT for argument tag -asmMonitorPassword
INFO: End of argument passing to stdin
INFO: Read:
INFO: Read: Configuring ASM failed with the following message:
INFO: Read: One or more diskgroup(s) creation failed as below:
INFO: Read: DiskGroup CRS creation failed with the following message:
INFO: Read: ORA-15018: diskgroup cannot be created
INFO: Read: ORA-15020: discovered duplicate ASM disk "CRS_0002"
INFO: Read:
INFO: Read:
INFO: Completed Plugin named: Automatic Storage Management Configuration Assistant


Solution:

Changed to the diskstring to ORCL as shown below and ran the below command as grid user

 /u01/app/grid/product/11.2.0/grid/bin/asmca -silent -oui_internal -configureASM -diskString ORCL:* -diskGroupName CRS -diskList ORCL:CRSVOL1,ORCL:CRSVOL2,ORCL:CRSVOL3 -redundancy EXTERNAL