CVE-2025-21807

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

block: fix queue freeze vs limits lock order in sysfs store methods

queue_attr_store() always freezes a device queue before calling the

attribute store operation. For attributes that control queue limits, the

store operation will also lock the queue limits with a call to

queue_limits_start_update(). However, some drivers (e.g. SCSI sd) may

need to issue commands to a device to obtain limit values from the

hardware with the queue limits locked. This creates a potential ABBA

deadlock situation if a user attempts to modify a limit (thus freezing

the device queue) while the device driver starts a revalidation of the

device queue limits.

Avoid such deadlock by not freezing the queue before calling the

->store_limit() method in struct queue_sysfs_entry and instead use the

queue_limits_commit_update_frozen helper to freeze the queue after taking

the limits lock.

This also removes taking the sysfs lock for the store_limit

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References