CVE-2026-99105 (GCVE-0-2026-99105)
Vulnerability from cvelistv5
Published
2026-10-28 10:34
Modified
2026-10-28 10:34
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
sched_ext: Fix stall when a task enqueued with SCX_ENQ_LAST lands back on its CPU's local DSQ
With SCX_OPS_ENQ_LAST, the last runnable task on a CPU is passed to
ops.enqueue() instead of being kept running. Exiting tasks without
SCX_OPS_ENQ_EXITING, migration disabled tasks without
SCX_OPS_ENQ_MIGRATION_DISABLED and tasks on an offline rq skip ops.enqueue()
and go straight to the local DSQ. This happens in put_prev_task_scx() after
the pick has settled on idle, so nothing reschedules the CPU, which idles
with the task queued until an unrelated wakeup lands on it or the watchdog
fires.
scx_mitosis, which sets SCX_OPS_ENQ_LAST without SCX_OPS_ENQ_EXITING, hit
this during mass cgroup teardown: exiting tasks stuck in exit_mmap() for
over 40 seconds.
A task put on the local DSQ runs, as anywhere else. If the SCX_ENQ_LAST
enqueue left the task on this CPU's local DSQ, set need_resched on the task
being switched in, as proxy_resched_idle() does. resched_curr() would flag
the task being put instead, and __schedule() clears that right after the
pick.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"kernel/sched/ext/ext.c",
"kernel/sched/ext/internal.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"versionType": "git"
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]
},
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"kernel/sched/ext/internal.h"
],
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"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.12"
},
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
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"version": "6.18.59",
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{
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"status": "unaffected",
"version": "7.2.13",
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{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
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}
],
"cpeApplicability": [
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"negate": false,
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Fix stall when a task enqueued with SCX_ENQ_LAST lands back on its CPU\u0027s local DSQ\n\nWith SCX_OPS_ENQ_LAST, the last runnable task on a CPU is passed to\nops.enqueue() instead of being kept running. Exiting tasks without\nSCX_OPS_ENQ_EXITING, migration disabled tasks without\nSCX_OPS_ENQ_MIGRATION_DISABLED and tasks on an offline rq skip ops.enqueue()\nand go straight to the local DSQ. This happens in put_prev_task_scx() after\nthe pick has settled on idle, so nothing reschedules the CPU, which idles\nwith the task queued until an unrelated wakeup lands on it or the watchdog\nfires.\n\nscx_mitosis, which sets SCX_OPS_ENQ_LAST without SCX_OPS_ENQ_EXITING, hit\nthis during mass cgroup teardown: exiting tasks stuck in exit_mmap() for\nover 40 seconds.\n\nA task put on the local DSQ runs, as anywhere else. If the SCX_ENQ_LAST\nenqueue left the task on this CPU\u0027s local DSQ, set need_resched on the task\nbeing switched in, as proxy_resched_idle() does. resched_curr() would flag\nthe task being put instead, and __schedule() clears that right after the\npick."
}
],
"providerMetadata": {
"dateUpdated": "2026-10-28T10:34:24.456Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
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"url": "https://git.kernel.org/stable/c/8d891c218016b6145993e082e7f732cb69dd0e29"
},
{
"url": "https://git.kernel.org/stable/c/396ba6f04da3fd1fb5a3d1c9535bef3f967f4e59"
},
{
"url": "https://git.kernel.org/stable/c/7a9df76679633cf26e0fea882a684012c6ec245a"
}
],
"title": "sched_ext: Fix stall when a task enqueued with SCX_ENQ_LAST lands back on its CPU\u0027s local DSQ",
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"cveId": "CVE-2026-99105",
"datePublished": "2026-10-28T10:34:24.456Z",
"dateReserved": "2026-09-25T10:25:14.391Z",
"dateUpdated": "2026-10-28T10:34:24.456Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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