CVE-2026-98865
Received Received - Intake

Race Condition in Linux Kernel Sched Ext

Publication date: 2026-10-18

Last updated on: 2026-10-18

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Don't run ops.dequeue() with a DSQ lock held ops.dequeue() is invoked with the source user DSQ's lock still held on the consume and move paths (scx_consume_dispatch_q(), move_task_between_dsqs()). A BPF scheduler which locks the source user DSQ from ops.dequeue() - e.g. by iterating it with bpf_iter_scx_dsq - self-deadlocks. ops.dequeue() can only call the "any" kfuncs and none of them can lock a builtin DSQ, so the global and bypass paths can't deadlock; however, all DSQ locks share one lockdep class, so iterating any user DSQ from ops.dequeue() on those paths trips the recursion check. Move the invocation after the DSQ unlock on all three paths. SCX_TASK_IN_CUSTODY is cleared under the lock serializing the transfer so that the callback is invoked exactly once.

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Meta Information

Published
2026-10-18
Last Modified
2026-10-18
Generated
2026-10-18
AI Q&A
2026-10-18
EPSS Evaluated
N/A
NVD
CVE-2026-98865
EUVD
EUVD-2026-103805

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
Linux Linux ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d
Linux Linux ebf1ccff79c43f860cbd2f9d6cfab9a462d0cb2d
Linux Linux 7.1

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Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability affects the Linux kernel's sched_ext component. It involves a deadlock issue where ops.dequeue() is called while holding a DSQ lock, which can cause self-deadlocks if a BPF scheduler locks the source user DSQ during ops.dequeue(). The fix moves the invocation of ops.dequeue() after releasing the DSQ lock on all relevant paths.

Impact Analysis

This vulnerability could lead to system hangs or crashes due to deadlocks in the Linux kernel's scheduler. If exploited, it may cause denial-of-service conditions, disrupting system operations and potentially leading to data loss or service unavailability.

Mitigation Strategies

Update the Linux kernel to a patched version where this vulnerability is resolved. Monitor kernel updates from your distribution vendor and apply them promptly.

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