Recently our staff tried to add disk strings to ASM diskgroups and the strings exceeded 1024 characters. We are on a oracle 184.108.40.206 on redhat linux. In the Docs, it says it should hold up to 4K, but when we added to the asm_diskstrings we got the following error and the ASM DB wouldn’t startup causing our production db to be down:
ORA-0600: [kslwt_validate_gwaitctx: magic], 
We looked many places (Including Metalink and Communities) and couldn’t find a ora-0600 error but did find a ora-7445 with the same code/error.
We opened a ticket and was notified that there is a bug with this error and a patch to fix it.
We were hitting Bug 18273830 where when the asm_diskstring becomes larger than 1024 characters it causes this failure. There is a one-off Patch available on My Oracle Support and 220.127.116.11 which will resolve this problem
Release Oracle 18.104.22.168.0
Platform Linux x86-64
Hope this helps, as there isn’t much documentation on this bug/error.