CVE-2025-22030

/// Technical description

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

mm: zswap: fix crypto_free_acomp() deadlock in zswap_cpu_comp_dead()

Currently, zswap_cpu_comp_dead() calls crypto_free_acomp() while holding

the per-CPU acomp_ctx mutex. crypto_free_acomp() then holds scomp_lock

(through crypto_exit_scomp_ops_async()).

On the other hand, crypto_alloc_acomp_node() holds the scomp_lock (through

crypto_scomp_init_tfm()), and then allocates memory. If the allocation

results in reclaim, we may attempt to hold the per-CPU acomp_ctx mutex.

The above dependencies can cause an ABBA deadlock. For example in the

following scenario:

(1) Task A running on CPU #1:

crypto_alloc_acomp_node()

Holds scomp_lock

Enters reclaim

Reads per_cpu_ptr(pool->acomp_ctx, 1)

(2) Task A is descheduled

(3) CPU #1 goes offline

zswap_cpu_comp_dead(CPU #1)

Holds per_cpu_ptr(pool->acomp_ctx, 1))

Calls crypto_free_acomp()

Waits for scomp_lock

(4) Task A running on CPU

/// 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