This vulnerability in the Linux kernel md subsystem affects raid456 reshape operations. During reshape, direct IO can sleep waiting for reshape progress while holding an active IO reference. If userspace freezes the reshape and writes to md/suspend_lo or md/suspend_hi, mddev_suspend() kills active IO and waits for all in-flight IO to drain. This creates a deadlock because the IO requires reshape progress to continue, but the reshape thread is frozen, so the active IO reference is never dropped and suspend never completes. The fix applies a wake to waiting raid456 IO during suspend when reshape is interrupted, allowing IO to abort, drop references, and let suspend finish. The issue is reproducible with the mdadm test tests/25raid456-reshape-deadlock.

The vulnerability can cause a deadlock during raid456 reshape suspend operations, resulting in a hang that prevents the system from completing suspend. This impacts availability but does not affect confidentiality or integrity.

A fix has been implemented in the Linux kernel to wake raid456 reshape waiters before suspend, preventing the deadlock. Users should apply the official kernel updates that include this fix. Patch status is not yet confirmed in this data; check the vendor or Linux kernel advisories for the current remediation guidance.