SB20260815151 - Deadlock in Linux kernel btrfs

Description

This security bulletin contains information about 1 vulnerability.

1) Deadlock (CVE-ID: CVE-2026-74318)

CWE-ID: CWE-833 - Deadlock

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a deadlock condition in the btrfs reflink inline extent cloning logic when cloning an inline extent to a destination offset greater than zero while the filesystem is mounted with flushoncommit. A local user can trigger crafted reflink and write activity to cause a denial of service.

The issue occurs when inline extent data is copied into a destination file beyond its current end of file, leading transaction commit and folio invalidation paths to wait on the same extent lock.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/06283034cec0fa357cbd85784ef7d3f5b2ce0790
• https://git.kernel.org/stable/c/2aa37c8ef1092c6f088e23a90bffefc672831c09
• https://git.kernel.org/stable/c/532085d00eb54c074bdeae648b194765239f4d11
• https://git.kernel.org/stable/c/ea3452726ccb6bcaa732f43cc57bb928eca3dd59