{"id":"CVE-2025-22030","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-22030","generatedAt":"2026-10-28T03:31:03.997Z","title":"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.…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm: zswap: fix crypto_free_acomp() deadlock in zswap_cpu_comp_dead()\n\nCurrently, zswap_cpu_comp_dead() calls crypto_free_acomp() while holding\nthe per-CPU acomp_ctx mutex.  crypto_free_acomp() then holds scomp_lock\n(through crypto_exit_scomp_ops_async()).\n\nOn the other hand, crypto_alloc_acomp_node() holds the scomp_lock (through\ncrypto_scomp_init_tfm()), and then allocates memory.  If the allocation\nresults in reclaim, we may attempt to hold the per-CPU acomp_ctx mutex.\n\nThe above dependencies can cause an ABBA deadlock.  For example in the\nfollowing scenario:\n\n(1) Task A running on CPU #1:\n    crypto_alloc_acomp_node()\n      Holds scomp_lock\n      Enters reclaim\n      Reads per_cpu_ptr(pool->acomp_ctx, 1)\n\n(2) Task A is descheduled\n\n(3) CPU #1 goes offline\n    zswap_cpu_comp_dead(CPU #1)\n      Holds per_cpu_ptr(pool->acomp_ctx, 1))\n      Calls crypto_free_acomp()\n      Waits for scomp_lock\n\n(4) Task A running on CPU #2:\n      Waits for per_cpu_ptr(pool->acomp_ctx, 1) // Read on CPU #1\n      DEADLOCK\n\nSince there is no requirement to call crypto_free_acomp() with the per-CPU\nacomp_ctx mutex held in zswap_cpu_comp_dead(), move it after the mutex is\nunlocked.  Also move the acomp_request_free() and kfree() calls for\nconsistency and to avoid any potential sublte locking dependencies in the\nfuture.\n\nWith this, only setting acomp_ctx fields to NULL occurs with the mutex\nheld.  This is similar to how zswap_cpu_comp_prepare() only initializes\nacomp_ctx fields with the mutex held, after performing all allocations\nbefore holding the mutex.\n\nOpportunistically, move the NULL check on acomp_ctx so that it takes place\nbefore the mutex dereference.","published":"2025-04-16T15:15:56.000Z","lastModified":"2026-06-17T08:44:53.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-667"],"affected":["linux/linux kernel"],"epss":{"score":0.00199,"percentile":0.09668,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.20%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/717d9c35deff6c33235693171bacbb03e9643fa4","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/747e3eec1d7d124ea90ed3d7b85369df8b4e36d2","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a8d18000e9d2d97aaf105f5f9b3b0e8a6fbf8b96","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c11bcbc0a517acf69282c8225059b2a8ac5fe628","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-22030","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}