FKIE_CVE-2026-53328

Vulnerability from fkie_nvd - Published: 2026-07-01 14:16 - Updated: 2026-07-01 14:16
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Don't warn on NULL cgrp_moving_from in scx_cgroup_move_task() A WARN fires when systemd's user manager writes "+cpu +memory +pids" to its own subtree_control while a sched_ext scheduler is loaded: WARNING: at kernel/sched/ext.c:3227 scx_cgroup_move_task+0xa8/0xb0 scx_cgroup_move_task+0xa8/0xb0 sched_move_task+0x134/0x290 cpu_cgroup_attach+0x39/0x70 cgroup_migrate_execute+0x37d/0x450 cgroup_update_dfl_csses+0x1e3/0x270 cgroup_subtree_control_write+0x3e7/0x440 scx_cgroup_can_attach() arms cgrp_moving_from only when a task's cpu cgroup changes. It can still be NULL when scx_cgroup_move_task() runs, through this sequence: Step Result --------------------------------- ---------------------------------- 1. cpu enabled on cgroup G cpu css = A 2. cpu toggled off then on for G A killed, B created (same cgroup) 3. an exiting task keeps A alive migration skips it, A now stale 4. +memory migrates G stale A vs current B pulls cpu in 5. cpu attach runs for all tasks hits a live, cpu-unchanged task 6. scx_cgroup_move_task() on it cgrp_moving_from NULL -> WARN The mismatch is that scx_cgroup_can_attach() keys on cgroup identity while migration drives the move on css identity, so a NULL cgrp_moving_from here is a legitimate css-only migration, not a missing prep. The call is already gated on cgrp_moving_from, so just drop the warning. ops.cgroup_prep_move() and ops.cgroup_move() stay paired.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/02e545c4297a26dbbc41df81b831e7f605bcd306
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0ffcad63b19a1cadb475c9f405a93607fdcd0d7c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bc75f5951fac4e49d175c4433fc08fb1ec01172f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/cdff2eb97be147d2ce52ac1327841068781f25dc
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "cdff2eb97be147d2ce52ac1327841068781f25dc",
              "status": "affected",
              "version": "8195136669661fdfe54e9a8923c33b31c92fc1da",
              "versionType": "git"
            },
            {
              "lessThan": "0ffcad63b19a1cadb475c9f405a93607fdcd0d7c",
              "status": "affected",
              "version": "8195136669661fdfe54e9a8923c33b31c92fc1da",
              "versionType": "git"
            },
            {
              "lessThan": "bc75f5951fac4e49d175c4433fc08fb1ec01172f",
              "status": "affected",
              "version": "8195136669661fdfe54e9a8923c33b31c92fc1da",
              "versionType": "git"
            },
            {
              "lessThan": "02e545c4297a26dbbc41df81b831e7f605bcd306",
              "status": "affected",
              "version": "8195136669661fdfe54e9a8923c33b31c92fc1da",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.12"
            },
            {
              "lessThan": "6.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.94",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.36",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Don\u0027t warn on NULL cgrp_moving_from in scx_cgroup_move_task()\n\nA WARN fires when systemd\u0027s user manager writes \"+cpu +memory +pids\" to\nits own subtree_control while a sched_ext scheduler is loaded:\n\n  WARNING: at kernel/sched/ext.c:3227 scx_cgroup_move_task+0xa8/0xb0\n   scx_cgroup_move_task+0xa8/0xb0\n   sched_move_task+0x134/0x290\n   cpu_cgroup_attach+0x39/0x70\n   cgroup_migrate_execute+0x37d/0x450\n   cgroup_update_dfl_csses+0x1e3/0x270\n   cgroup_subtree_control_write+0x3e7/0x440\n\nscx_cgroup_can_attach() arms cgrp_moving_from only when a task\u0027s cpu\ncgroup changes. It can still be NULL when scx_cgroup_move_task() runs,\nthrough this sequence:\n\n  Step                               Result\n  ---------------------------------  ----------------------------------\n  1. cpu enabled on cgroup G         cpu css = A\n  2. cpu toggled off then on for G   A killed, B created (same cgroup)\n  3. an exiting task keeps A alive   migration skips it, A now stale\n  4. +memory migrates G              stale A vs current B pulls cpu in\n  5. cpu attach runs for all tasks   hits a live, cpu-unchanged task\n  6. scx_cgroup_move_task() on it    cgrp_moving_from NULL -\u003e WARN\n\nThe mismatch is that scx_cgroup_can_attach() keys on cgroup identity\nwhile migration drives the move on css identity, so a NULL cgrp_moving_from\nhere is a legitimate css-only migration, not a missing prep.\n\nThe call is already gated on cgrp_moving_from, so just drop the warning.\nops.cgroup_prep_move() and ops.cgroup_move() stay paired."
    }
  ],
  "id": "CVE-2026-53328",
  "lastModified": "2026-07-01T14:16:40.650",
  "metrics": {},
  "published": "2026-07-01T14:16:40.650",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/02e545c4297a26dbbc41df81b831e7f605bcd306"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0ffcad63b19a1cadb475c9f405a93607fdcd0d7c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bc75f5951fac4e49d175c4433fc08fb1ec01172f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/cdff2eb97be147d2ce52ac1327841068781f25dc"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}


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