In the Linux kernel, a mis‑ordering of locks in kfree_rcu() can trigger a deadlock with kswapd. When kfree_rcu() allocates memory with __GFP_KSWAPD_RECLAIM while holding the scheduler’s pi_lock, waking kswapd causes pi_lock to be attempted again, resulting in a circular dependency. The primary impact is a denial‑of‑service that can stall the entire system, as the kernel enters a deadlock state.

The flaw exists in the Linux kernel source, affecting all kernel versions that compile with the default mm/slab implementation and have not applied the guarded change. No specific version range is supplied, so any unpatched kernel that could invoke kfree_rcu() under pi_lock is potentially vulnerable.

EPSS score is lower than 1%, indicating a very low exploitation probability, and the flaw is not listed in the CISA KEV catalog. The CVSS score for this vulnerability is 4.7, indicating a moderate severity. Based on the description, it is inferred that an attacker would need kernel‑level control to invoke kfree_rcu while holding pi_lock, which would constitute a local‑privilege scenario. Based on the description, it is inferred that the conditions that lead to the deadlock are rare and require precise timing; an attacker who can meet them could force a system halt, resulting in a low‑impact denial of service. Exploit development is non‑trivial, so the overall risk remains moderate, but the impact is significant if triggered.