Linus issued a warning: Do not use Linux Kernel 5.12-rc1

Last week, Linux Kernel 5.12-rc1 released after several twists and turns, but just the day after the release, Linus immediately sent a warning email to the kernel mailing list, telling everyone not to use the latest 5.12-rc1 kernel (especially uses the swap file to run), and asks the maintainer not to branch from 5.12-rc1, so as not to bring the problem to future versions.

Before the email was sent, Linus had renamed the “v5.12-rc1” tag in the public git tree to “v5.12-rc1-dontuse” to remind users not to use it. According to Linus’s explanation, the kernel of version 5.12-rc1 severely damaged the processing of swap files, which would cause the file system to be overwritten by random swap data, and also cause large sections of metadata to be overwritten. Damage to metadata may cause the entire file system to be unmounted and unusable.

Linus says:

The bad news is that the reason we support swapfiles in the first place is that they do end up having some flexibility advantages, and so some people do use them for that reason. If so, do not use rc1. Thus the renaming of the tag.