Description (CNA)
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.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 2dc79362302922cb18f35e262712b5e58de65442 before 262dadc619e69ebeb97affd334cd1078a9704e98; affected eef4f71b46a9929ac33e968538c9dd5d96a02460 before 1fa22de588a65880d6fe54c38c87fffe7d519f60; affected 684a78183c54c23e70d1cba320f7fc184604210b before a0269e928728f970c782319fee53d92d4ea4e512; affected 18c0456ea2615b1a743a6db739c74411c3b42bc6 before 90e254f18b8c224460082329dd5c42fd30995c2f; affected 91840be8f710370607f949a627e070896faeddb8 before 0833b2b84c2fc1387f8165f0cbf6a02d67f647a5; affected 91840be8f710370607f949a627e070896faeddb8 before f2539c56c74691e7a88af6372ba2b48c06ed2fe4; affected 81b582784518196eff1050212a046bc29d3a05dd; affected 6.1.175 before 6.1.178; affected 6.6.142 before 6.6.145; affected 6.12.92 before 6.12.95; affected 6.18.34 before 6.18.38; affected 7.0.11 before 7.1 |
| Linux / Linux | affected 7.1; unaffected 0 before 7.1; unaffected 6.1.178 through 6.1.*; unaffected 6.6.145 through 6.6.*; unaffected 6.12.95 through 6.12.*; unaffected 6.18.38 through 6.18.*; unaffected 7.1.3 through 7.1.*; unaffected 7.2 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/262dadc619e69ebeb97affd334cd1078a9704e98
- https://git.kernel.org/stable/c/1fa22de588a65880d6fe54c38c87fffe7d519f60
- https://git.kernel.org/stable/c/a0269e928728f970c782319fee53d92d4ea4e512
- https://git.kernel.org/stable/c/90e254f18b8c224460082329dd5c42fd30995c2f
- https://git.kernel.org/stable/c/0833b2b84c2fc1387f8165f0cbf6a02d67f647a5
- https://git.kernel.org/stable/c/f2539c56c74691e7a88af6372ba2b48c06ed2fe4