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.
References
Impacted products
Vendor | Product | Version |
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{ "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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Sightings
Author | Source | Type | Date |
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Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
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- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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