Linux Kernel Admin Queue Stuck Condition Vulnerability in pds_core Component

A vulnerability in the Linux kernel's pds_core component can lead to an admin queue (adminq) overflow and a stuck condition, preventing commands from being processed. The adminq is managed by a lock that allows only one command to be posted at a time, but completions occur in a different context. This discrepancy can result in multiple adminq commands being posted sequentially, all waiting for completion. The adminq request queue on the firmware side is only 16 entries long and lacks proper overflow or stuck condition prevention. As a result, the adminq can become stuck, halting command processing and completion notifications from the firmware. The vulnerability has been addressed by limiting the number of outstanding adminq commands to 16, ensuring the adminq does not get stuck or overflow.

Impact

The vulnerability could cause the admin queue to become stuck, leading to a denial of service where commands are not processed and completions are not sent by the firmware.