Access to view blocking sessions in sql server 2008

Hi,

One of my client wrote a stored procedure. we scheduled this SP in a job. while job is running, it is blocking other sessions. It is happening frequently. So, client is asking me to grant permission to view blocking session( want to execute sp_who2). Could you please advise me, which permission I need to give. I don't like to give access other than sp_who2. Please advise.

Thanks.

Raja.

Thanks, Raja