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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 7.1 | 7.2.10 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 7.2.10-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 24.04 LTS | linux-riscv +25 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.14 +1 | No fix yet | — |
Advisories 1
- WID-SEC-2026-4019 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026