CVE-2026-64211

Description

In the Linux kernel, the following vulnerability has been resolved: srcu: Don't queue workqueue handlers to never-online CPUs While an srcu_struct structure is in the midst of switching from CPU-0 to all-CPUs state, it can attempt to invoke callbacks for CPUs that have never been online. Worse yet, it can attempt in invoke callbacks for CPUs that never will be online, even including imaginary CPUs not in cpu_possible_mask. This can cause hangs on s390, which is not set up to deal with workqueue handlers being scheduled on such CPUs. This commit therefore causes Tree SRCU to refrain from queueing workqueue handlers on CPUs that have not yet (and might never) come online. Because callbacks are not invoked on CPUs that have not been online, it is an error to invoke call_srcu(), synchronize_srcu(), or synchronize_srcu_expedited() on a CPU that is not yet fully online. However, it turns out to be less code to redirect the callbacks from too-early invocations of call_srcu() than to warn about such invocations. This commit therefore also redirects callbacks queued on not-yet-fully-online CPUs to the boot CPU.

CVSS 3.1

5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS

0.14% probability · 4th percentile

Public exploits

None in Exploit-DB

CISA KEV

Not listed

Affected

linux/linux kernel

Source

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.