fkie_cve-2025-38066
Vulnerability from fkie_nvd
Published
2025-06-18 10:15
Modified
2025-06-18 13:46
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: dm cache: prevent BUG_ON by blocking retries on failed device resumes A cache device failing to resume due to mapping errors should not be retried, as the failure leaves a partially initialized policy object. Repeating the resume operation risks triggering BUG_ON when reloading cache mappings into the incomplete policy object. Reproduce steps: 1. create a cache metadata consisting of 512 or more cache blocks, with some mappings stored in the first array block of the mapping array. Here we use cache_restore v1.0 to build the metadata. cat <<EOF >> cmeta.xml <superblock uuid="" block_size="128" nr_cache_blocks="512" \ policy="smq" hint_width="4"> <mappings> <mapping cache_block="0" origin_block="0" dirty="false"/> </mappings> </superblock> EOF dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" cache_restore -i cmeta.xml -o /dev/mapper/cmeta --metadata-version=2 dmsetup remove cmeta 2. wipe the second array block of the mapping array to simulate data degradations. mapping_root=$(dd if=/dev/sdc bs=1c count=8 skip=192 \ 2>/dev/null | hexdump -e '1/8 "%u\n"') ablock=$(dd if=/dev/sdc bs=1c count=8 skip=$((4096*mapping_root+2056)) \ 2>/dev/null | hexdump -e '1/8 "%u\n"') dd if=/dev/zero of=/dev/sdc bs=4k count=1 seek=$ablock 3. try bringing up the cache device. The resume is expected to fail due to the broken array block. dmsetup create cmeta --table "0 8192 linear /dev/sdc 0" dmsetup create cdata --table "0 65536 linear /dev/sdc 8192" dmsetup create corig --table "0 524288 linear /dev/sdc 262144" dmsetup create cache --notable dmsetup load cache --table "0 524288 cache /dev/mapper/cmeta \ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0" dmsetup resume cache 4. try resuming the cache again. An unexpected BUG_ON is triggered while loading cache mappings. dmsetup resume cache Kernel logs: (snip) ------------[ cut here ]------------ kernel BUG at drivers/md/dm-cache-policy-smq.c:752! Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 0 UID: 0 PID: 332 Comm: dmsetup Not tainted 6.13.4 #3 RIP: 0010:smq_load_mapping+0x3e5/0x570 Fix by disallowing resume operations for devices that failed the initial attempt.
Impacted products
Vendor Product Version



{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm cache: prevent BUG_ON by blocking retries on failed device resumes\n\nA cache device failing to resume due to mapping errors should not be\nretried, as the failure leaves a partially initialized policy object.\nRepeating the resume operation risks triggering BUG_ON when reloading\ncache mappings into the incomplete policy object.\n\nReproduce steps:\n\n1. create a cache metadata consisting of 512 or more cache blocks,\n   with some mappings stored in the first array block of the mapping\n   array. Here we use cache_restore v1.0 to build the metadata.\n\ncat \u003c\u003cEOF \u003e\u003e cmeta.xml\n\u003csuperblock uuid=\"\" block_size=\"128\" nr_cache_blocks=\"512\" \\\npolicy=\"smq\" hint_width=\"4\"\u003e\n  \u003cmappings\u003e\n    \u003cmapping cache_block=\"0\" origin_block=\"0\" dirty=\"false\"/\u003e\n  \u003c/mappings\u003e\n\u003c/superblock\u003e\nEOF\ndmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\"\ncache_restore -i cmeta.xml -o /dev/mapper/cmeta --metadata-version=2\ndmsetup remove cmeta\n\n2. wipe the second array block of the mapping array to simulate\n   data degradations.\n\nmapping_root=$(dd if=/dev/sdc bs=1c count=8 skip=192 \\\n2\u003e/dev/null | hexdump -e \u00271/8 \"%u\\n\"\u0027)\nablock=$(dd if=/dev/sdc bs=1c count=8 skip=$((4096*mapping_root+2056)) \\\n2\u003e/dev/null | hexdump -e \u00271/8 \"%u\\n\"\u0027)\ndd if=/dev/zero of=/dev/sdc bs=4k count=1 seek=$ablock\n\n3. try bringing up the cache device. The resume is expected to fail\n   due to the broken array block.\n\ndmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\"\ndmsetup create cdata --table \"0 65536 linear /dev/sdc 8192\"\ndmsetup create corig --table \"0 524288 linear /dev/sdc 262144\"\ndmsetup create cache --notable\ndmsetup load cache --table \"0 524288 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0\"\ndmsetup resume cache\n\n4. try resuming the cache again. An unexpected BUG_ON is triggered\n   while loading cache mappings.\n\ndmsetup resume cache\n\nKernel logs:\n\n(snip)\n------------[ cut here ]------------\nkernel BUG at drivers/md/dm-cache-policy-smq.c:752!\nOops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI\nCPU: 0 UID: 0 PID: 332 Comm: dmsetup Not tainted 6.13.4 #3\nRIP: 0010:smq_load_mapping+0x3e5/0x570\n\nFix by disallowing resume operations for devices that failed the\ninitial attempt."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: dm cache: impide BUG_ON bloqueando los reintentos en reinicios de dispositivos fallidos. Un dispositivo de cach\u00e9 que no se reanuda debido a errores de mapeo no debe reintentarse, ya que el fallo deja un objeto de pol\u00edtica parcialmente inicializado. Repetir la operaci\u00f3n de reanudaci\u00f3n corre el riesgo de activar BUG_ON al recargar los mapeos de cach\u00e9 en el objeto de pol\u00edtica incompleto. Reproducir los pasos: 1. Crear metadatos de cach\u00e9 que consten de 512 o m\u00e1s bloques de cach\u00e9, con algunos mapeos almacenados en el primer bloque de la matriz de mapeo. Aqu\u00ed usamos cache_restore v1.0 para generar los metadatos. cat \u0026lt;\u0026lt;\u0026gt; cmeta.xml      EOF dmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\" cache_restore -i cmeta.xml -o /dev/mapper/cmeta --metadata-version=2 dmsetup remove cmeta 2. wipe the second array block of the mapping array to simulate data degradations. mapping_root=$(dd if=/dev/sdc bs=1c count=8 skip=192 \\ 2\u0026gt;/dev/null | hexdump -e \u00271/8 \"%u\\n\"\u0027) ablock=$(dd if=/dev/sdc bs=1c count=8 skip=$((4096*mapping_root+2056)) \\ 2\u0026gt;/dev/null | hexdump -e \u00271/8 \"%u\\n\"\u0027) dd if=/dev/zero of=/dev/sdc bs=4k count=1 seek=$ablock 3. try bringing up the cache device. The resume is expected to fail due to the broken array block. dmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\" dmsetup create cdata --table \"0 65536 linear /dev/sdc 8192\" dmsetup create corig --table \"0 524288 linear /dev/sdc 262144\" dmsetup create cache --notable dmsetup load cache --table \"0 524288 cache /dev/mapper/cmeta \\ /dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0\" dmsetup resume cache 4. Intente reanudar la cach\u00e9 de nuevo. Se activa un BUG_ON inesperado al cargar las asignaciones de cach\u00e9. dmsetup resume cache Registros del kernel: (snip) ------------[ cortar aqu\u00ed ]------------ \u00a1ERROR del kernel en drivers/md/dm-cache-policy-smq.c:752! Oops: c\u00f3digo de operaci\u00f3n no v\u00e1lido: 0000 [#1] PREEMPT SMP KASAN NOPTI CPU: 0 UID: 0 PID: 332 Comm: dmsetup No contaminado 6.13.4 #3 RIP: 0010:smq_load_mapping+0x3e5/0x570 Se soluciona no permitiendo operaciones de reanudaci\u00f3n para dispositivos que fallaron en el intento inicial."
    }
  ],
  "id": "CVE-2025-38066",
  "lastModified": "2025-06-18T13:46:52.973",
  "metrics": {},
  "published": "2025-06-18T10:15:39.620",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/00586b78eeb7c626a14ca13453a1631f88a7cf36"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/025c8f477625eb39006ded650e7d027bcfb20e79"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3986ef4a9b6a0d9c28bc325d8713beba5e67586f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5da692e2262b8f81993baa9592f57d12c2703dea"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c5356a5e80442131e2714d0d26bb110590e4e568"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c614584c2a66b538f469089ac089457a34590c14"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cc80a5cc520939d0a7d071cc4ae4b3c55ef171d0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f3128e3074e8af565cc6a66fe3384a56df87f803"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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