CVE-2026-98864

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task ebf1ccff79c4 ("sched_ext: Fix ops.dequeue() semantics") moved the final ops_state store in scx_dispatch_enqueue() after the DSQ unlock so that the custody update and ops.dequeue() precede it. A task can thus be found on a DSQ while still SCX_OPSS_DISPATCHING. The dequeue and core-sched pick paths wait for the state to clear in ops_dequeue() but the reenqueue paths don't. A reenqueue in that window runs ops.enqueue() and sets SCX_OPSS_QUEUED before the dispatch has completed. The dispatcher's final store then overwrites it with SCX_OPSS_NONE and finish_dispatch() drops every later dispatch of the task. Wait for SCX_OPSS_DISPATCHING to clear before dequeueing a task for reenqueue, the same way ops_dequeue() does.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-10-18 16:17:40.877000

Last modified

2026-10-19 10:19:50.473000

View original CVE JSON

{
  "id": "CVE-2026-98864",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-10-18T16:17:40.877",
  "lastModified": "2026-10-19T10:19:50.473",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task\n\nebf1ccff79c4 (\"sched_ext: Fix ops.dequeue() semantics\") moved the final\nops_state store in scx_dispatch_enqueue() after the DSQ unlock so that the\ncustody update and ops.dequeue() precede it. A task can thus be found on a\nDSQ while still SCX_OPSS_DISPATCHING.\n\nThe dequeue and core-sched pick paths wait for the state to clear in\nops_dequeue() but the reenqueue paths don't. A reenqueue in that window runs\nops.enqueue() and sets SCX_OPSS_QUEUED before the dispatch has completed.\nThe dispatcher's final store then overwrites it with SCX_OPSS_NONE and\nfinish_dispatch() drops every later dispatch of the task.\n\nWait for SCX_OPSS_DISPATCHING to clear before dequeueing a task for\nreenqueue, the same way ops_dequeue() does."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "kernel/sched/ext/ext.c",
            "kernel/sched/ext/internal.h",
            "kernel/sched/ext/sub.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d",
              "lessThan": "43457bf6550044c40bd6d3fcdf9ea66f5a55d139",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d",
              "lessThan": "7de9a6fb44eae4f05e68c805d58b9c618815adfa",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "kernel/sched/ext/ext.c",
            "kernel/sched/ext/internal.h",
            "kernel/sched/ext/sub.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "7.1",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "7.1",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.10",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/43457bf6550044c40bd6d3fcdf9ea66f5a55d139",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7de9a6fb44eae4f05e68c805d58b9c618815adfa",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}