Linux Kernel F2FS Missing Read Bio Submission Vulnerability

A vulnerability in the Linux kernel's F2FS (Flash-Friendly File System) can lead to a deadlock situation where read operations on large folios are not completed. This issue arises because the function responsible for reading data can retain a read bio (block I/O) across multiple readahead folios. If an error occurs with a later folio before its blocks are added to the bio, the folio is not considered part of the bio, and the error handling routine exits without submitting the bio. As a result, the bio for earlier folios remains unsubmitted, causing those folios to miss read completion. Readers can then be left waiting indefinitely on the locked folios.

Impact

This vulnerability can cause a deadlock by leaving folios locked and waiting for read completions that never occur, effectively stalling any processes dependent on those folios.

Remediation

Users can upgrade to the patched version of the Linux kernel available in the Linux kernel stable tree. The specific commit addressing this vulnerability is 48c92559e7b66fdc3cbc74f6e152e66ec0150a0a.