Exadata X6-2 full and half racks were patched recently with 220.127.116.11.7 Aug/2018 quarterly patch set. An ORA-07445 started to observe and the cellsrv intermittently crashing with ORA-07445 error.
Following error is noticed in the cellsrv alert.log:
ORA-07445: exception encountered: core dump [0000000000000000+0]  [0x000000000]   
The above is registered as a bug whenever cell storage is patched with 18.104.22.168.7 or 22.214.171.124.8. Therefore, if you are planning to patch your cell storage software with one of the above versions, ensure you also apply patch 28181789 to avoid cellsrv intermittently crashing with ORA-07445 error. Otherwise, you need to upgrade the storage software with 18.1.5.
Customer may experience intermittent cellsrv crashes with ORA-07445: [0000000000000000+0]  [0x000000000] after upgrading storage cell software version to 126.96.36.199.7 or 188.8.131.52.8
Upgrade the Storage cell software to 184.108.40.206.7 or 220.127.116.11.8
Bug 28181789 - ORA-07445: [0000000000000000+0] AFTER UPGRADING CELL TO 18.104.22.168.7
Patch 28181789 is available for 22.214.171.124.7 and 126.96.36.199.8 Storage software releases. Follow the README to instructions to apply the patch.
apply 18.1.5 and later which includes the fix of 28181789
xadata: Intermittent cellsrv crashes with ORA-07445: [0000000000000000+0]  [0x000000000] after upgrading to 188.8.131.52.7 or 184.108.40.206.8 (Doc ID 2421083.1)