CVE-2026-64250 - Vulnerability Details

Vendors	Products
Linux	Linux Kernel

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

Type	Values Removed	Values Added
Description		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.
Title		LoongArch: Report dying CPU to RCU in stop_this_cpu()
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/0833b2b84c2fc1387f8165f0cbf6a02d67f647a5 https://git.kernel.org/stable/c/1fa22de588a65880d6fe54c38c87fffe7d519f60 https://git.kernel.org/stable/c/262dadc619e69ebeb97affd334cd1078a9704e98 https://git.kernel.org/stable/c/90e254f18b8c224460082329dd5c42fd30995c2f https://git.kernel.org/stable/c/a0269e928728f970c782319fee53d92d4ea4e512 https://git.kernel.org/stable/c/f2539c56c74691e7a88af6372ba2b48c06ed2fe4

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-64250", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.773Z", "datePublished": "2026-07-24T15:31:17.021Z", "dateUpdated": "2026-07-24T15:31:17.021Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-07-24T15:31:17.021Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nLoongArch: Report dying CPU to RCU in stop_this_cpu()\n\nThis is a port of MIPS commit 9f3f3bdc6d9dac1 (\"MIPS: smp: report dying\nCPU to RCU in stop_this_cpu()\"). smp_send_stop() parks all secondary\nCPUs in stop_this_cpu(). And the function marks the CPU offline for the\nscheduler via set_cpu_online(false) but never informs RCU, so RCU keeps\nexpecting a quiescent state from CPUs that are now spinning forever with\ninterrupts disabled.\n\nAs long as nothing waits for an RCU grace period after smp_send_stop()\nthis is harmless, which is why it went unnoticed. However, since commit\n91840be8f710370 (\"irq_work: Fix use-after-free in irq_work_single() on\nPREEMPT_RT\"), irq_work_sync() calls synchronize_rcu() on architectures\nwithout an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt()\nreturns false. Any irq_work_sync() issued in the reboot/shutdown/halt\npath after smp_send_stop() then blocks on a grace period that can never\ncomplete, hanging the reboot:\n\n WARNING: CPU: 0 PID: 15 at kernel/irq_work.c:144 irq_work_queue_on\n ...\n rcu: INFO: rcu_sched detected stalls on CPUs/tasks:\n rcu: Offline CPU 1 blocking current GP.\n rcu: Offline CPU 2 blocking current GP.\n rcu: Offline CPU 3 blocking current GP.\n\nThis issue needs some hacks to reproduce, and it was not noticed on\nLoongArch because arch_irq_work_has_interrupt() usually returns true.\n\nCall rcutree_report_cpu_dead() once interrupts are disabled, mirroring\nthe generic CPU-hotplug offline path, so RCU stops waiting on the parked\nCPUs and grace periods can still complete. LoongArch shuts down all CPUs\nhere without going through the CPU-hotplug mechanism, so this report is\nnot otherwise issued."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["arch/loongarch/kernel/smp.c"], "versions": [{"version": "2dc79362302922cb18f35e262712b5e58de65442", "lessThan": "262dadc619e69ebeb97affd334cd1078a9704e98", "status": "affected", "versionType": "git"}, {"version": "eef4f71b46a9929ac33e968538c9dd5d96a02460", "lessThan": "1fa22de588a65880d6fe54c38c87fffe7d519f60", "status": "affected", "versionType": "git"}, {"version": "684a78183c54c23e70d1cba320f7fc184604210b", "lessThan": "a0269e928728f970c782319fee53d92d4ea4e512", "status": "affected", "versionType": "git"}, {"version": "18c0456ea2615b1a743a6db739c74411c3b42bc6", "lessThan": "90e254f18b8c224460082329dd5c42fd30995c2f", "status": "affected", "versionType": "git"}, {"version": "91840be8f710370607f949a627e070896faeddb8", "lessThan": "0833b2b84c2fc1387f8165f0cbf6a02d67f647a5", "status": "affected", "versionType": "git"}, {"version": "91840be8f710370607f949a627e070896faeddb8", "lessThan": "f2539c56c74691e7a88af6372ba2b48c06ed2fe4", "status": "affected", "versionType": "git"}, {"version": "81b582784518196eff1050212a046bc29d3a05dd", "status": "affected", "versionType": "git"}, {"version": "6.1.175", "lessThan": "6.1.178", "status": "affected", "versionType": "semver"}, {"version": "6.6.142", "lessThan": "6.6.145", "status": "affected", "versionType": "semver"}, {"version": "6.12.92", "lessThan": "6.12.95", "status": "affected", "versionType": "semver"}, {"version": "6.18.34", "lessThan": "6.18.38", "status": "affected", "versionType": "semver"}, {"version": "7.0.11", "lessThan": "7.1", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["arch/loongarch/kernel/smp.c"], "versions": [{"version": "7.1", "status": "affected"}, {"version": "0", "lessThan": "7.1", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.95", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.38", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.1.3", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2-rc1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.175", "versionEndExcluding": "6.1.178"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.142", "versionEndExcluding": "6.6.145"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.92", "versionEndExcluding": "6.12.95"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18.34", "versionEndExcluding": "6.18.38"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1", "versionEndExcluding": "7.1.3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1", "versionEndExcluding": "7.2-rc1"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0.11"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/262dadc619e69ebeb97affd334cd1078a9704e98"}, {"url": "https://git.kernel.org/stable/c/1fa22de588a65880d6fe54c38c87fffe7d519f60"}, {"url": "https://git.kernel.org/stable/c/a0269e928728f970c782319fee53d92d4ea4e512"}, {"url": "https://git.kernel.org/stable/c/90e254f18b8c224460082329dd5c42fd30995c2f"}, {"url": "https://git.kernel.org/stable/c/0833b2b84c2fc1387f8165f0cbf6a02d67f647a5"}, {"url": "https://git.kernel.org/stable/c/f2539c56c74691e7a88af6372ba2b48c06ed2fe4"}], "title": "LoongArch: Report dying CPU to RCU in stop_this_cpu()", "x_generator": {"engine": "bippy-1.2.0"}}}}

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