Medium 5.5Published Jul 24, 2026

CVE-2026-64250LoongArch: Report dying CPU to RCU in stop_this_cpu()

Updated under an hour ago (Oct 28, 2026, 11:50 AM ET)

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Exploited in the last 30 days

In the Linux kernel, the following vulnerability has been resolved: LoongArch: Report dying CPU to RCU in stop_this_cpu() This is a port of MIPS commit 9f3f3bdc6d9dac1 ("MIPS: smp: report dying CPU to RCU in stop_this_cpu()"). smp_send_stop() parks all secondary CPUs in stop_this_cpu(). And the function marks the CPU offline for the scheduler via set_cpu_online(false) but never informs RCU, so RCU keeps expecting a quiescent state from CPUs that are now spinning forever with interrupts disabled. As long as nothing waits for an RCU grace period after smp_send_stop() this is harmless, which is why it went unnoticed. However, since commit 91840be8f710370 ("irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT"), irq_work_sync() calls synchronize_rcu() on architectures without an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt() returns false. Any irq_work_sync() issued in the reboot/shutdown/halt path after smp_send_stop() then blocks on a grace period that can never complete, hanging the reboot: WARNING: CPU: 0 PID: 15 at kernel/irq_work.c:144 irq_work_queue_on ... rcu: INFO: rcu_sched detected stalls on CPUs/tasks: rcu: Offline CPU 1 blocking current GP. rcu: Offline CPU 2 blocking current GP. rcu: Offline CPU 3 blocking current GP. This issue needs some hacks to reproduce, and it was not noticed on LoongArch because arch_irq_work_has_interrupt() usually returns true. Call rcutree_report_cpu_dead() once interrupts are disabled, mirroring the generic CPU-hotplug offline path, so RCU stops waiting on the parked CPUs and grace periods can still complete. LoongArch shuts down all CPUs here without going through the CPU-hotplug mechanism, so this report is not otherwise issued.

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Analyzed
Record last updated: Aug 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 2dc79362302922cb18f35e262712b5e58de65442 before 262dadc619e69ebeb97affd334cd1078a9704e98; from eef4f71b46a9929ac33e968538c9dd5d96a02460 before 1fa22de588a65880d6fe54c38c87fffe7d519f60; from 684a78183c54c23e70d1cba320f7fc184604210b before a0269e928728f970c782319fee53d92d4ea4e512; from 18c0456ea2615b1a743a6db739c74411c3b42bc6 before 90e254f18b8c224460082329dd5c42fd30995c2f; 91840be8f710370607f949a627e070896faeddb8 builds before 0833b2b84c2fc1387f8165f0cbf6a02d67f647a5; from 91840be8f710370607f949a627e070896faeddb8 before f2539c56c74691e7a88af6372ba2b48c06ed2fe4; 81b582784518196eff1050212a046bc29d3a05dd; from 6.1.175 before 6.1.178; and 4 more ranges	CNA record
linux linux_kernel linux:linux_kernel	from 6.1.175 before 6.1.178; from 6.6.142 before 6.6.145; from 6.12.92 before 6.12.95; from 6.18.34 before 6.18.38; from 7.0.11 before 7.1; from 7.1.1 before 7.1.3; 7.1; 7.1; and 3 more ranges	NVD

References

References

https://git.kernel.org/stable/c/262dadc619e69ebeb97affd334cd1078a9704e98	patch
https://git.kernel.org/stable/c/1fa22de588a65880d6fe54c38c87fffe7d519f60	patch
https://git.kernel.org/stable/c/a0269e928728f970c782319fee53d92d4ea4e512	patch
https://git.kernel.org/stable/c/90e254f18b8c224460082329dd5c42fd30995c2f	patch
https://git.kernel.org/stable/c/0833b2b84c2fc1387f8165f0cbf6a02d67f647a5	patch
https://git.kernel.org/stable/c/f2539c56c74691e7a88af6372ba2b48c06ed2fe4	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.