Checking the rcu_sched messages finds repeated mention of cdrom scans / 2021-07-12

I was going through some rcu_sched messages and noticed kernel routines related to the cdrom drive showed up a few times in the tasks that were 'behind'.

[335894.319961]  [<ffffffffc03d864a>] ? scsi_execute+0x12a/0x1d0 [scsi_mod]
[335894.320702]  [<ffffffffc03da586>] ? scsi_execute_req_flags+0x96/0x100 [scsi_mod]
[335894.321820]  [<ffffffffc04a7703>] ? sr_check_events+0xc3/0x2c0 [sr_mod]
[335894.322551]  [<ffffffffb58224a5>] ? __switch_to_asm+0x35/0x70
[335894.323256]  [<ffffffffb58224b1>] ? __switch_to_asm+0x41/0x70
[335894.323906]  [<ffffffffc047d05a>] ? cdrom_check_events+0x1a/0x30 [cdrom]
[335894.324545]  [<ffffffffc04a8289>] ? sr_block_check_events+0x89/0xe0 [sr_mod]
[335894.325186]  [<ffffffffb551a9a9>] ? disk_check_events+0x69/0x150

Because the virtual machines don't do anything with the virtual cdrom after the first installation I'm removing them from all virtual machines and see what that does for these messages.