CVE-2026-93220

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Keep kick_sync waiting on the rq's own CPU kick_sync_wait_bal_cb() assumes it runs on the rq's CPU from the __schedule() tail: the snapshots it compares against live in that CPU's percpu area and the busy-wait runs with the rq lock dropped and IRQs enabled. However, dispatch can now drop the rq lock while the callback sits queued, and rq lock takers in that window (the sched class change paths, the scx task iterator) flush pending balance callbacks on release, running the callback on a foreign CPU. Such a run compares against unrelated snapshots and can deadlock when the executing CPU is itself a wait target. Bail on a foreign CPU and leave the wait state alone. The wait only observes progress that the resched kicks already guarantee and the rq's next wait picks up the stale cpus_to_sync bits.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

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

Published

2026-09-24 16:17:17.197000

Last modified

2026-10-19 10:17:12.933000

View original CVE JSON

{
  "id": "CVE-2026-93220",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-24T16:17:17.197",
  "lastModified": "2026-10-19T10:17:12.933",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Keep kick_sync waiting on the rq's own CPU\n\nkick_sync_wait_bal_cb() assumes it runs on the rq's CPU from the\n__schedule() tail: the snapshots it compares against live in that CPU's\npercpu area and the busy-wait runs with the rq lock dropped and IRQs\nenabled.\n\nHowever, dispatch can now drop the rq lock while the callback sits queued,\nand rq lock takers in that window (the sched class change paths, the scx\ntask iterator) flush pending balance callbacks on release, running the\ncallback on a foreign CPU. Such a run compares against unrelated snapshots\nand can deadlock when the executing CPU is itself a wait target.\n\nBail on a foreign CPU and leave the wait state alone. The wait only observes\nprogress that the resched kicks already guarantee and the rq's next wait\npicks up the stale cpus_to_sync bits."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "kernel/sched/ext/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "4c95380701f58b8112f0b891de8d160e4199e19d",
              "lessThan": "c736ea0fe7b4df920da6bd43a81c5eeecadcc8be",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "4c95380701f58b8112f0b891de8d160e4199e19d",
              "lessThan": "e0253dd04beb03e79477c5ef4768b11135687206",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "kernel/sched/ext/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.19",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.19",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.4",
              "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/c736ea0fe7b4df920da6bd43a81c5eeecadcc8be",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e0253dd04beb03e79477c5ef4768b11135687206",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}