CVE-2021-46987

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description The issue is related to a deadlock that occurs when cloning inline extents and using qgroups in the btrfs file system. This happens because when reserving metadata space for a transaction, the system may need to flush existing delalloc in case there is not enough free space. A mechanism was introduced to prevent a deadlock, but when using qgroups, a transaction also reserves metadata qgroup space, which can result in flushing delalloc and cause a deadlock. The deadlock occurs because flushing delalloc requires locking the file range in the inode's iotree, and the range was already locked at the beginning of the clone operation.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.