CVE-2026-98344 (GCVE-0-2026-98344)
Vulnerability from cvelistv5
Published
2026-10-06 08:46
Modified
2026-10-19 09:17
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: dmaengine: Fix device kref underflow in dma_chan_put() dma_chan_get() takes chan->device->ref only on the slow path: /* no kref on fast path */ if (chan->client_count) { __module_get(owner); chan->client_count++; return 0; } if (!try_module_get(owner)) return -ENODEV; if (!dma_device_get(chan->device)) { // calls kref_get_unless_zero() dma_chan_put() drops the ref unconditionally, so every fast-path get/put pair drops one extra device reference. The bug fires when two conditions hold together: a non-private provider has a persistent client holding chan->client_count > 0 and another client cycles dmaengine_get()/dmaengine_put(). When the kref hits zero, the subsequent dma_find_channel() returns NULL even though the provider module is still loaded. Fix this by dropping device->ref only on the last put, matching the single slow-path get.
References
Impacted products
Vendor Product Version
Linux Linux Version: 8ad342a863590b24ce77681b7e081363fb3333f7
Version: 8ad342a863590b24ce77681b7e081363fb3333f7
Version: 8ad342a863590b24ce77681b7e081363fb3333f7
Version: 8ad342a863590b24ce77681b7e081363fb3333f7
Version: 8ad342a863590b24ce77681b7e081363fb3333f7
Version: 8ad342a863590b24ce77681b7e081363fb3333f7
Version: 8ad342a863590b24ce77681b7e081363fb3333f7
Version: 8ad342a863590b24ce77681b7e081363fb3333f7
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndmaengine: Fix device kref underflow in dma_chan_put()\n\ndma_chan_get() takes chan-\u003edevice-\u003eref only on the slow path:\n\n\t/* no kref on fast path */\n\tif (chan-\u003eclient_count) {\n\t\t__module_get(owner);\n\t\tchan-\u003eclient_count++;\n\t\treturn 0;\n\t}\n\tif (!try_module_get(owner))\n\t\treturn -ENODEV;\n\tif (!dma_device_get(chan-\u003edevice)) { // calls kref_get_unless_zero()\n\ndma_chan_put() drops the ref unconditionally, so every fast-path\nget/put pair drops one extra device reference.\n\nThe bug fires when two conditions hold together: a non-private\nprovider has a persistent client holding chan-\u003eclient_count \u003e 0\nand another client cycles dmaengine_get()/dmaengine_put().\nWhen the kref hits zero, the subsequent dma_find_channel() returns\nNULL even though the provider module is still loaded.\n\nFix this by dropping device-\u003eref only on the last put, matching the\nsingle slow-path get."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:17:55.263Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/036b527f92570206da4b8c40b38f8d689e29d0f3"
        },
        {
          "url": "https://git.kernel.org/stable/c/5fb1797a8c9485e40e5492fa0338ab5c7d1f3fef"
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        {
          "url": "https://git.kernel.org/stable/c/57f7f1c6827be7d8f80feca48d2125fb91c6f6ed"
        },
        {
          "url": "https://git.kernel.org/stable/c/7c3f4ce651d43705f9ec7f778f642a90d5ff4fba"
        },
        {
          "url": "https://git.kernel.org/stable/c/de2677e57d3161390d8a508f08cddec6ef7e4b23"
        },
        {
          "url": "https://git.kernel.org/stable/c/1a0d9b406febf23054ad595fd47b29325e70fb2d"
        },
        {
          "url": "https://git.kernel.org/stable/c/77906ac448d2fa81fa710ae26c0e591ebdc81154"
        },
        {
          "url": "https://git.kernel.org/stable/c/44dab659064eb5c10adb0306510eebe848ed592d"
        }
      ],
      "title": "dmaengine: Fix device kref underflow in dma_chan_put()",
      "x_generator": {
        "engine": "bippy-1.2.0"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98344",
    "datePublished": "2026-10-06T08:46:33.997Z",
    "dateReserved": "2026-09-25T10:25:14.343Z",
    "dateUpdated": "2026-10-19T09:17:55.263Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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