fkie_cve-2025-22030
Vulnerability from fkie_nvd
Published
2025-04-16 15:15
Modified
2025-04-17 20:22
Severity ?
Summary
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 #2: Waits for per_cpu_ptr(pool->acomp_ctx, 1) // Read on CPU #1 DEADLOCK Since there is no requirement to call crypto_free_acomp() with the per-CPU acomp_ctx mutex held in zswap_cpu_comp_dead(), move it after the mutex is unlocked. Also move the acomp_request_free() and kfree() calls for consistency and to avoid any potential sublte locking dependencies in the future. With this, only setting acomp_ctx fields to NULL occurs with the mutex held. This is similar to how zswap_cpu_comp_prepare() only initializes acomp_ctx fields with the mutex held, after performing all allocations before holding the mutex. Opportunistically, move the NULL check on acomp_ctx so that it takes place before the mutex dereference.
Impacted products
Vendor Product Version



{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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-\u003eacomp_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-\u003eacomp_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-\u003eacomp_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."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: mm: zswap: correcci\u00f3n del bloqueo de crypto_free_acomp() en zswap_cpu_comp_dead(). Actualmente, zswap_cpu_comp_dead() llama a crypto_free_acomp() mientras mantiene el mutex acomp_ctx por CPU. A continuaci\u00f3n, crypto_free_acomp() mantiene scomp_lock (mediante crypto_exit_scomp_ops_async()). Por otro lado, crypto_alloc_acomp_node() mantiene scomp_lock (mediante crypto_scomp_init_tfm()) y luego asigna memoria. Si la asignaci\u00f3n resulta en una recuperaci\u00f3n, podemos intentar mantener el mutex acomp_ctx por CPU. Las dependencias anteriores pueden causar un bloqueo de ABBA. Por ejemplo, en el siguiente escenario: (1) Tarea A ejecut\u00e1ndose en la CPU n.\u00ba 1: crypto_alloc_acomp_node() Retiene scomp_lock Ingresa a recuperaci\u00f3n Lee per_cpu_ptr(pool-\u0026gt;acomp_ctx, 1) (2) La tarea A se desprograma (3) La CPU n.\u00ba 1 se desconecta zswap_cpu_comp_dead(CPU n.\u00ba 1) Retiene per_cpu_ptr(pool-\u0026gt;acomp_ctx, 1)) Llama a crypto_free_acomp() Espera a scomp_lock (4) Tarea A ejecut\u00e1ndose en la CPU n.\u00ba 2: Espera a per_cpu_ptr(pool-\u0026gt;acomp_ctx, 1) // Lee en la CPU n.\u00ba 1 BLOQUEO INTERMEDIO Dado que no es necesario llamar a crypto_free_acomp() con el mutex acomp_ctx por CPU retenido en zswap_cpu_comp_dead(), mu\u00e9valo despu\u00e9s de que se desbloquee el mutex. Tambi\u00e9n se desplazan las llamadas acomp_request_free() y kfree() para mantener la coherencia y evitar posibles dependencias de bloqueo sutil en el futuro. Con esto, solo se establece el valor NULL de los campos acomp_ctx con el mutex retenido. Esto es similar a c\u00f3mo zswap_cpu_comp_prepare() solo inicializa los campos acomp_ctx con el mutex retenido, despu\u00e9s de realizar todas las asignaciones antes de retener el mutex. Oportunistamente, se desplaza la comprobaci\u00f3n de valores NULL en acomp_ctx para que se realice antes de la desreferencia del mutex."
    }
  ],
  "id": "CVE-2025-22030",
  "lastModified": "2025-04-17T20:22:16.240",
  "metrics": {},
  "published": "2025-04-16T15:15:55.607",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/717d9c35deff6c33235693171bacbb03e9643fa4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/747e3eec1d7d124ea90ed3d7b85369df8b4e36d2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a8d18000e9d2d97aaf105f5f9b3b0e8a6fbf8b96"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c11bcbc0a517acf69282c8225059b2a8ac5fe628"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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