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.
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
No data available yet.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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Sun, 18 Oct 2026 16:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | sched_ext: Wait for SCX_OPSS_DISPATCHING before reenqueueing a task | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-10-18T15:51:25.532Z
Reserved: 2026-09-25T10:25:14.377Z
Link: CVE-2026-98864
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-18T16:17:40.877
Modified: 2026-10-18T16:17:40.877
Link: CVE-2026-98864
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.