CVE-2026-74319

Received Received - Intake

Deadlock in Btrfs Zoned Filesystem Data Relocation

Publication date: 2026-08-15

Last updated on: 2026-08-17

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: zoned: fix deadlock waiting for ticket during data relocation When performing data relocation on a zoned filesystem, BTRFS can deadlock in handle_reserve_tickets(). The relocation process is waiting on a space reservation ticket that can never be fulfilled, because the relocation itself is the operation responsible for freeing up that space. Fix this by introducing a new flush state, BTRFS_RESERVE_FLUSH_ZONED_RELOCATION, specifically for data chunk allocation during zoned relocation. Like BTRFS_RESERVE_FLUSH_FREE_SPACE_INODE, this state uses priority_reclaim_data_space() instead of the normal flushing path, which avoids re-entering the relocation code and breaking the deadlock cycle. In btrfs_alloc_data_chunk_ondemand(), select this new flush state when the inode belongs to a data relocation root on a zoned filesystem.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-08-15

Last Modified

2026-08-17

Generated

2026-09-04

AI Q&A

2026-08-15

EPSS Evaluated

2026-09-03

NVD

CVE-2026-74319

EUVD

EUVD-2026-59466

Affected Vendors & Products

Vendor	Product	Version / Range
linux_kernel	btrfs	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability is a deadlock issue in the Linux kernel's BTRFS filesystem when handling zoned storage. During data relocation, the system waits for a space reservation ticket that cannot be fulfilled because the relocation process itself is responsible for freeing the required space. This creates a deadlock where the system is stuck waiting indefinitely.

Detection Guidance

This vulnerability is specific to the Linux kernel's BTRFS filesystem with zoned mode enabled. Detection requires checking for deadlocks during data relocation operations. Monitor kernel logs for BTRFS-related deadlock warnings or system hangs during disk operations. No direct commands are provided in the context to detect this issue.

Impact Analysis

This vulnerability can cause system hangs or crashes during data relocation operations on BTRFS filesystems using zoned storage. This may lead to data unavailability, application failures, or system instability while the deadlock persists.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards. It is a Linux kernel issue related to a deadlock in the BTRFS filesystem during data relocation on zoned storage, which could lead to system hangs or crashes but does not involve data exposure or unauthorized access.

Mitigation Strategies

Apply the kernel patch that resolves this issue. If patching is not immediately possible, avoid using BTRFS in zoned mode or disable data relocation operations. Monitor system logs for deadlocks and ensure regular backups are maintained.

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