Description
In the Linux kernel, the following vulnerability has been resolved:
sched_ext: Derive SCX_RQ_IN_WAKEUP from the core enqueue flags
schedule_deferred_locked() skips scheduling a deferred action while
SCX_RQ_IN_WAKEUP is set and relies on the task_woken_scx() call that follows
a wakeup enqueue to run it. enqueue_task_scx() sets the flag from the merged
enqueue flags, which include the flags stashed for a remote activation.
move_remote_task_to_local_dsq() thus sets SCX_RQ_IN_WAKEUP on the
destination rq when the moved task was woken up, although no
task_woken_scx() follows that activation.
An IMMED insert into a busy destination requests a local reenqueue during
that enqueue. The request gets linked but not scheduled and stays pending
until an unrelated wakeup or preemption on that CPU runs the deferred
actions. The IMMED task sits behind the running task in the meantime. If
nothing runs them before the scheduler is disabled, the request outlives the
scheduler and points into its freed per-cpu area, which the next scheduler
dereferences from run_deferred().
Test the core enqueue flags for the wakeup bit. Only the core's wakeup path
is followed by task_woken_scx().
sched_ext: Derive SCX_RQ_IN_WAKEUP from the core enqueue flags
schedule_deferred_locked() skips scheduling a deferred action while
SCX_RQ_IN_WAKEUP is set and relies on the task_woken_scx() call that follows
a wakeup enqueue to run it. enqueue_task_scx() sets the flag from the merged
enqueue flags, which include the flags stashed for a remote activation.
move_remote_task_to_local_dsq() thus sets SCX_RQ_IN_WAKEUP on the
destination rq when the moved task was woken up, although no
task_woken_scx() follows that activation.
An IMMED insert into a busy destination requests a local reenqueue during
that enqueue. The request gets linked but not scheduled and stays pending
until an unrelated wakeup or preemption on that CPU runs the deferred
actions. The IMMED task sits behind the running task in the meantime. If
nothing runs them before the scheduler is disabled, the request outlives the
scheduler and points into its freed per-cpu area, which the next scheduler
dereferences from run_deferred().
Test the core enqueue flags for the wakeup bit. Only the core's wakeup path
is followed by task_woken_scx().
Published:
2026-10-18
Score:
n/a
EPSS:
n/a
KEV:
No
Impact:
n/a
Action:
n/a
Analysis
No analysis available yet.
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 |
|
|||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No remediation available yet.
Tracking
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Advisories
No advisories yet.
References
History
Sun, 18 Oct 2026 15:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: sched_ext: Derive SCX_RQ_IN_WAKEUP from the core enqueue flags schedule_deferred_locked() skips scheduling a deferred action while SCX_RQ_IN_WAKEUP is set and relies on the task_woken_scx() call that follows a wakeup enqueue to run it. enqueue_task_scx() sets the flag from the merged enqueue flags, which include the flags stashed for a remote activation. move_remote_task_to_local_dsq() thus sets SCX_RQ_IN_WAKEUP on the destination rq when the moved task was woken up, although no task_woken_scx() follows that activation. An IMMED insert into a busy destination requests a local reenqueue during that enqueue. The request gets linked but not scheduled and stays pending until an unrelated wakeup or preemption on that CPU runs the deferred actions. The IMMED task sits behind the running task in the meantime. If nothing runs them before the scheduler is disabled, the request outlives the scheduler and points into its freed per-cpu area, which the next scheduler dereferences from run_deferred(). Test the core enqueue flags for the wakeup bit. Only the core's wakeup path is followed by task_woken_scx(). | |
| Title | sched_ext: Derive SCX_RQ_IN_WAKEUP from the core enqueue flags | |
| 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: 2026-10-18T15:15:15.775Z
Reserved: 2026-09-25T10:25:14.350Z
Link: CVE-2026-98463
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-10-18T16:16:56.770
Modified: 2026-10-18T16:16:56.770
Link: CVE-2026-98463
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.