sql server 2012 master database log is corrupted sql 2012 master database is corrupted, i have recent backup of master, what will happen to my user databases after restoring master, do i have to restore all db's from latest backups? 

Thanks
If any database is corrupted, I start to worry about the storage it lives on. If you haven't identified the root cause of the corruption yet - like a bad storage driver, a bad storage cable, a failing RAID array, or maybe even a known bug in SQL Server - then I'd start by assuming that the server and its storage is not completely reliable.

I'd start by failing over to a different server on different storage, and run CHECKDB against all of your user databases (not just master) to make sure they're okay. (Don't think that a clean CHECKDB on the existing server means you're out of the woods - master might have just been the first place that storage decided to corrupt.)

For much more details, check out my post, What to Do When DBCC CHECKDB Reports Corruption, which includes a checklist on:


Turn off your backup-delete jobs
Query the msdb.dbo.suspect_pages table
If you're using a SAN, alert the storage team
Alert the application owners and stakeholders
Review the history of your CHECKDB and backup jobs


And more.