CVE-2026-99105
Full vulnerability record from the local CVENow database.
Description
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.
View original CVE JSON
{
"id": "CVE-2026-99105",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-10-28T11:17:29.847",
"lastModified": "2026-10-30T13:21:45.317",
"vulnStatus": "Received",
"cveTags": [],
"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's 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's 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."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"kernel/sched/ext/ext.c",
"kernel/sched/ext/internal.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "f0e1a0643a59bf1f922fa209cec86a170b784f3f",
"lessThan": "ea47eec058fc1b6a3c3c54870d24a8bdcb3e204d",
"versionType": "git",
"status": "affected"
},
{
"version": "f0e1a0643a59bf1f922fa209cec86a170b784f3f",
"lessThan": "8d891c218016b6145993e082e7f732cb69dd0e29",
"versionType": "git",
"status": "affected"
},
{
"version": "f0e1a0643a59bf1f922fa209cec86a170b784f3f",
"lessThan": "396ba6f04da3fd1fb5a3d1c9535bef3f967f4e59",
"versionType": "git",
"status": "affected"
},
{
"version": "f0e1a0643a59bf1f922fa209cec86a170b784f3f",
"lessThan": "7a9df76679633cf26e0fea882a684012c6ec245a",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"kernel/sched/ext/ext.c",
"kernel/sched/ext/internal.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "6.12",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.12",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.115",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.59",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2.13",
"lessThanOrEqual": "7.2.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/396ba6f04da3fd1fb5a3d1c9535bef3f967f4e59",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/7a9df76679633cf26e0fea882a684012c6ec245a",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/8d891c218016b6145993e082e7f732cb69dd0e29",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/ea47eec058fc1b6a3c3c54870d24a8bdcb3e204d",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}