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CVE-2026-74392 (GCVE-0-2026-74392)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:59 – Updated: 2026-08-17 05:18
VLAI
Title
dm: limit target bio polling to one shot
Summary
In the Linux kernel, the following vulnerability has been resolved: dm: limit target bio polling to one shot dm_poll_bio() is the ->poll_bio() callback for a stacked dm device. The caller only knows about the dm queue, so it may decide to do a spinning poll if it thinks a single queue is being polled. Passing those flags unchanged to the mapped clone lets blk_mq_poll() spin on a target queue from inside dm_poll_bio(). With io_uring IOPOLL on a dm-stripe target this can keep a task in dm_poll_bio() -> bio_poll() -> blk_mq_poll() long enough to trigger an RCU CPU stall, before io_uring gets back to io_iopoll_check() and its need_resched() check. Keep dm's ->poll_bio() bounded by forcing one-shot polling for target bios. The caller can invoke dm_poll_bio() again if it wants to keep polling, and it also gets a chance to reap completions or reschedule between passes.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: f22ecf9c14c12918e30f2179ef516e99eb8b2e49 , < 6c4ede3b771adbb3bf21ad4e8b8f2f6f6120c4f7 (git)
Affected: f22ecf9c14c12918e30f2179ef516e99eb8b2e49 , < 5aa0f9231cbacade065cedd8e9b5ebd067231171 (git)
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Linux Linux Affected: 6.19
Unaffected: 0 , < 6.19 (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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      "affected": [
        {
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          "product": "Linux",
          "programFiles": [
            "drivers/md/dm.c"
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndm: limit target bio polling to one shot\n\ndm_poll_bio() is the -\u003epoll_bio() callback for a stacked dm device.\nThe caller only knows about the dm queue, so it may decide to do a\nspinning poll if it thinks a single queue is being polled. Passing those\nflags unchanged to the mapped clone lets blk_mq_poll() spin on a target\nqueue from inside dm_poll_bio().\n\nWith io_uring IOPOLL on a dm-stripe target this can keep a task in\n\n  dm_poll_bio() -\u003e bio_poll() -\u003e blk_mq_poll()\n\nlong enough to trigger an RCU CPU stall, before io_uring gets back to\nio_iopoll_check() and its need_resched() check.\n\nKeep dm\u0027s -\u003epoll_bio() bounded by forcing one-shot polling for target\nbios. The caller can invoke dm_poll_bio() again if it wants to keep\npolling, and it also gets a chance to reap completions or reschedule\nbetween passes."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:18:31.175Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6c4ede3b771adbb3bf21ad4e8b8f2f6f6120c4f7"
        },
        {
          "url": "https://git.kernel.org/stable/c/5aa0f9231cbacade065cedd8e9b5ebd067231171"
        }
      ],
      "title": "dm: limit target bio polling to one shot",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74392",
    "datePublished": "2026-08-15T05:59:05.787Z",
    "dateReserved": "2026-08-15T05:44:03.891Z",
    "dateUpdated": "2026-08-17T05:18:31.175Z",
    "state": "PUBLISHED"
  },
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      "date": "2026-09-04",
      "epss": "0.00156",
      "percentile": "0.0508"
    },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-20T22:26:33+00:00",
      "cve": "CVE-2026-74392",
      "id": "CVE-2026-74392",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "90",
      "product_status:known_not_affected": "184",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: dm: limit target bio polling to one shot",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74392.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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