CVE-2025-21807

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> block: fix queue freeze vs limits lock order in sysfs store methods<br /> <br /> queue_attr_store() always freezes a device queue before calling the<br /> attribute store operation. For attributes that control queue limits, the<br /> store operation will also lock the queue limits with a call to<br /> queue_limits_start_update(). However, some drivers (e.g. SCSI sd) may<br /> need to issue commands to a device to obtain limit values from the<br /> hardware with the queue limits locked. This creates a potential ABBA<br /> deadlock situation if a user attempts to modify a limit (thus freezing<br /> the device queue) while the device driver starts a revalidation of the<br /> device queue limits.<br /> <br /> Avoid such deadlock by not freezing the queue before calling the<br /> -&gt;store_limit() method in struct queue_sysfs_entry and instead use the<br /> queue_limits_commit_update_frozen helper to freeze the queue after taking<br /> the limits lock.<br /> <br /> This also removes taking the sysfs lock for the store_limit method as<br /> it doesn&amp;#39;t protect anything here, but creates even more nesting.<br /> Hopefully it will go away from the actual sysfs methods entirely soon.<br /> <br /> (commit log adapted from a similar patch from Damien Le Moal)