Medium 5.5Published Jul 1, 2026

CVE-2026-53328sched_ext: Don't warn on NULL cgrp_moving_from in scx_cgroup_move_task()

Updated under an hour ago (Oct 26, 2026, 9:40 PM ET)

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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.

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Analyzed
Record last updated: Jul 1, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 8195136669661fdfe54e9a8923c33b31c92fc1da before cdff2eb97be147d2ce52ac1327841068781f25dc; 8195136669661fdfe54e9a8923c33b31c92fc1da builds before 0ffcad63b19a1cadb475c9f405a93607fdcd0d7c; from 8195136669661fdfe54e9a8923c33b31c92fc1da before bc75f5951fac4e49d175c4433fc08fb1ec01172f; 8195136669661fdfe54e9a8923c33b31c92fc1da builds before 02e545c4297a26dbbc41df81b831e7f605bcd306	CNA record
linux linux_kernel linux:linux_kernel	from 6.12 before 6.12.94; from 6.13 before 6.18.36; from 6.19 before 7.0.13; 7.1; 7.1; 7.1; 7.1; 7.1; and 1 more ranges	NVD

References

References

https://git.kernel.org/stable/c/cdff2eb97be147d2ce52ac1327841068781f25dc	patch
https://git.kernel.org/stable/c/0ffcad63b19a1cadb475c9f405a93607fdcd0d7c	patch
https://git.kernel.org/stable/c/bc75f5951fac4e49d175c4433fc08fb1ec01172f	patch
https://git.kernel.org/stable/c/02e545c4297a26dbbc41df81b831e7f605bcd306	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.