{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "5b26f7b920f76b2b9cc398c252a9e35e44bf5bb9"
            },
            {
              "fixed": "ca685511f7afd42cdcbb0feea42e5d332d384251"
            },
            {
              "fixed": "5e7b2cc8fae9ec2a5bc53311191d2faaff75a4b5"
            },
            {
              "fixed": "7ea601daa0153e19cd1c6e6b300348c70c05fe77"
            },
            {
              "fixed": "7e0ffb72de8aa3b25989c2d980e81b829c577010"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.12.0"
            },
            {
              "fixed": "6.12.82"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.22"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "6.19.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31733.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Fix stale direct dispatch state in ddsp_dsq_id\n\n@p-\u003escx.ddsp_dsq_id can be left set (non-SCX_DSQ_INVALID) triggering a\nspurious warning in mark_direct_dispatch() when the next wakeup's\nops.select_cpu() calls scx_bpf_dsq_insert(), such as:\n\n WARNING: kernel/sched/ext.c:1273 at scx_dsq_insert_commit+0xcd/0x140\n\nThe root cause is that ddsp_dsq_id was only cleared in dispatch_enqueue(),\nwhich is not reached in all paths that consume or cancel a direct dispatch\nverdict.\n\nFix it by clearing it at the right places:\n\n - direct_dispatch(): cache the direct dispatch state in local variables\n   and clear it before dispatch_enqueue() on the synchronous path. For\n   the deferred path, the direct dispatch state must remain set until\n   process_ddsp_deferred_locals() consumes them.\n\n - process_ddsp_deferred_locals(): cache the dispatch state in local\n   variables and clear it before calling dispatch_to_local_dsq(), which\n   may migrate the task to another rq.\n\n - do_enqueue_task(): clear the dispatch state on the enqueue path\n   (local/global/bypass fallbacks), where the direct dispatch verdict is\n   ignored.\n\n - dequeue_task_scx(): clear the dispatch state after dispatch_dequeue()\n   to handle both the deferred dispatch cancellation and the holding_cpu\n   race, covering all cases where a pending direct dispatch is\n   cancelled.\n\n - scx_disable_task(): clear the direct dispatch state when\n   transitioning a task out of the current scheduler. Waking tasks may\n   have had the direct dispatch state set by the outgoing scheduler's\n   ops.select_cpu() and then been queued on a wake_list via\n   ttwu_queue_wakelist(), when SCX_OPS_ALLOW_QUEUED_WAKEUP is set. Such\n   tasks are not on the runqueue and are not iterated by scx_bypass(),\n   so their direct dispatch state won't be cleared. Without this clear,\n   any subsequent SCX scheduler that tries to direct dispatch the task\n   will trigger the WARN_ON_ONCE() in mark_direct_dispatch().",
  "id": "CVE-2026-31733",
  "modified": "2026-07-15T01:49:20.933809175Z",
  "published": "2026-05-01T14:14:31.558Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5e7b2cc8fae9ec2a5bc53311191d2faaff75a4b5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7e0ffb72de8aa3b25989c2d980e81b829c577010"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7ea601daa0153e19cd1c6e6b300348c70c05fe77"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ca685511f7afd42cdcbb0feea42e5d332d384251"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31733.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31733"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "summary": "sched_ext: Fix stale direct dispatch state in ddsp_dsq_id"
}