Cloudanix VulnDB

CVE-2023-52839

None

CVSS

—

EPSS

0.2%

Published

May 21, 2024

CISA due date

—

Cloudanix analysis

Monitor only SSVC: Track

A bug in the Linux kernel's performance tracking on certain hardware could produce unexpected system warnings when running diagnostic commands.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Theoretical
Impact
Denial Of Service
Component
OS kernel
Class
Other
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

The flaw causes unnecessary inter-CPU broadcasts via on_each_cpu_cond_mask when starting SBI performance counters on RISC-V, invoking smp_call_function_many_cond with invalid conditions and producing kernel warnings.

Why it matters to the business

Systems running affected kernels may encounter unexpected warnings or instability during performance monitoring on RISC-V hardware, disrupting diagnostics without affecting core workloads; the low EPSS and lack of KEV listing indicate minimal widespread operational risk even 877 days after publication.

How an attack unfolds

A local user invokes perf record with multiple hardware events and large mmap buffers, causing the scheduler tick to call perf_event_task_tick which reaches riscv_pmu_start and pmu_sbi_ctr_start; the erroneous broadcast path then triggers the warning in smp_call_function_many_cond. No named threat actors or ransomware campaigns have been observed exploiting this issue.

How to fix it

Upgrade the Linux kernel to version 6.6.2 or apply the fix from commit 85be1a73fd298ed3fd060dfce97caef5f9928c57 in the stable repository; disable or avoid the affected perf event combinations on RISC-V until patched.

How to confirm the fix worked

Confirm the running kernel version meets or exceeds 6.6.2; re-execute the triggering perf record command and verify absence of the smp_call_function_many_cond warning in dmesg or kernel logs.

Typical attack path

  1. Execute perf record with cycles:k and instructions:k events plus large -m buffer
  2. Trigger scheduler tick via process execution
  3. Invoke riscv_pmu_start and pmu_sbi_ctr_start
  4. Enter on_each_cpu_cond_mask leading to smp_call_function_many_cond warning

How to detect it

Search kernel logs and dmesg for the warning string from smp_call_function_many_cond triggered after perf record invocations; correlate with RISC-V SBI perf counter start events in scheduler tick paths.

  • WARNING: CPU:.*smp_call_function_many_cond
  • pmu_sbi_ctr_start
  • riscv_pmu_start

What your security team should do

  • Apply kernel updates to 6.6.2 or newer on all RISC-V systems within standard patch cycles
  • Add kernel warning patterns for smp_call_function_many_cond to monitoring rules
  • Review perf usage policies on RISC-V deployments given the low but non-zero EPSS score

The record

In the Linux kernel, the following vulnerability has been resolved: drivers: perf: Do not broadcast to other cpus when starting a counter This command: $ perf record -e cycles:k -e instructions:k -c 10000 -m 64M dd if=/dev/zero of=/dev/null count=1000 gives rise to this kernel warning: [ 444.364395] WARNING: CPU: 0 PID: 104 at kernel/smp.c:775 smp_call_function_many_cond+0x42c/0x436 [ 444.364515] Modules linked in: [ 444.364657] CPU: 0 PID: 104 Comm: perf-exec Not tainted 6.6.0-rc6-00051-g391df82e8ec3-dirty #73 [ 444.364771] Hardware name: riscv-virtio,qemu (DT) [ 444.364868] epc : smp_call_function_many_cond+0x42c/0x436 [ 444.364917] ra : on_each_cpu_cond_mask+0x20/0x32 [ 444.364948] epc : ffffffff8009f9e0 ra : ffffffff8009fa5a sp : ff20000000003800 [ 444.364966] gp : ffffffff81500aa0 tp : ff60000002b83000 t0 : ff200000000038c0 [ 444.364982] t1 : ffffffff815021f0 t2 : 000000000000001f s0 : ff200000000038b0 [ 444.364998] s1 : ff60000002c54d98 a0 : ff60000002a73940 a1 : 0000000000000000 [ 444.365013] a2 : 0000000000000000 a3 : 0000000000000003 a4 : 0000000000000100 [ 444.365029] a5 : 0000000000010100 a6 : 0000000000f00000 a7 : 0000000000000000 [ 444.365044] s2 : 0000000000000000 s3 : ffffffffffffffff s4 : ff60000002c54d98 [ 444.365060] s5 : ffffffff81539610 s6 : ffffffff80c20c48 s7 : 0000000000000000 [ 444.365075] s8 : 0000000000000000 s9 : 0000000000000001 s10: 0000000000000001 [ 444.365090] s11: ffffffff80099394 t3 : 0000000000000003 t4 : 00000000eac0c6e6 [ 444.365104] t5 : 0000000400000000 t6 : ff60000002e010d0 [ 444.365120] status: 0000000200000100 badaddr: 0000000000000000 cause: 0000000000000003 [ 444.365226] [<ffffffff8009f9e0>] smp_call_function_many_cond+0x42c/0x436 [ 444.365295] [<ffffffff8009fa5a>] on_each_cpu_cond_mask+0x20/0x32 [ 444.365311] [<ffffffff806e90dc>] pmu_sbi_ctr_start+0x7a/0xaa [ 444.365327] [<ffffffff806e880c>] riscv_pmu_start+0x48/0x66 [ 444.365339] [<ffffffff8012111a>] perf_adjust_freq_unthr_context+0x196/0x1ac [ 444.365356] [<ffffffff801237aa>] perf_event_task_tick+0x78/0x8c [ 444.365368] [<ffffffff8003faf4>] scheduler_tick+0xe6/0x25e [ 444.365383] [<ffffffff8008a042>] update_process_times+0x80/0x96 [ 444.365398] [<ffffffff800991ec>] tick_sched_handle+0x26/0x52 [ 444.365410] [<ffffffff800993e4>] tick_sched_timer+0x50/0x98 [ 444.365422] [<ffffffff8008a6aa>] __hrtimer_run_queues+0x126/0x18a [ 444.365433] [<ffffffff8008b350>] hrtimer_interrupt+0xce/0x1da [ 444.365444] [<ffffffff806cdc60>] riscv_timer_interrupt+0x30/0x3a [ 444.365457] [<ffffffff8006afa6>] handle_percpu_devid_irq+0x80/0x114 [ 444.365470] [<ffffffff80065b82>] generic_handle_domain_irq+0x1c/0x2a [ 444.365483] [<ffffffff8045faec>] riscv_intc_irq+0x2e/0x46 [ 444.365497] [<ffffffff808a9c62>] handle_riscv_irq+0x4a/0x74 [ 444.365521] [<ffffffff808aa760>] do_irq+0x7c/0x7e [ 444.365796] ---[ end trace 0000000000000000 ]--- That's because the fix in commit 3fec323339a4 ("drivers: perf: Fix panic in riscv SBI mmap support") was wrong since there is no need to broadcast to other cpus when starting a counter, that's only needed in mmap when the counters could have already been started on other cpus, so simply remove this broadcast.

Affected packages

Ecosystem Package Introduced Fixed
Linux Kernel 6.6.0 6.6.2
Ubuntu:16.04:LTS linux-hwe-edge 0 No fix
Ubuntu:18.04:LTS linux-aws-5.0 0 No fix
Ubuntu:18.04:LTS linux-aws-5.3 0 No fix
Ubuntu:18.04:LTS linux-azure 0 No fix
Ubuntu:18.04:LTS linux-azure-5.3 0 No fix
Ubuntu:18.04:LTS linux-azure-edge 0 No fix
Ubuntu:18.04:LTS linux-gcp 0 No fix
Ubuntu:18.04:LTS linux-gcp-5.3 0 No fix
Ubuntu:18.04:LTS linux-gke-4.15 0 No fix
Ubuntu:18.04:LTS linux-gke-5.4 0 No fix
Ubuntu:18.04:LTS linux-gkeop-5.4 0 No fix
Ubuntu:18.04:LTS linux-hwe 0 No fix
Ubuntu:18.04:LTS linux-hwe-edge 0 No fix
Ubuntu:18.04:LTS linux-oem 0 No fix
Ubuntu:18.04:LTS linux-oracle-5.0 0 No fix
Ubuntu:18.04:LTS linux-oracle-5.3 0 No fix
Ubuntu:20.04:LTS linux 0 5.4.0-9.12
Ubuntu:20.04:LTS linux-aws 0 5.4.0-1005.5
Ubuntu:20.04:LTS linux-aws-5.11 0 No fix
Ubuntu:20.04:LTS linux-aws-5.13 0 No fix
Ubuntu:20.04:LTS linux-aws-5.15 0 5.15.0-1014.18~20.04.1
Ubuntu:20.04:LTS linux-aws-5.8 0 No fix
Ubuntu:20.04:LTS linux-azure 0 5.4.0-1006.6
Ubuntu:20.04:LTS linux-azure-5.11 0 No fix
Ubuntu:20.04:LTS linux-azure-5.13 0 No fix
Ubuntu:20.04:LTS linux-azure-5.15 0 5.15.0-1007.8~20.04.1
Ubuntu:20.04:LTS linux-azure-5.8 0 No fix
Ubuntu:20.04:LTS linux-azure-fde 0 No fix
Ubuntu:20.04:LTS linux-azure-fde-5.15 0 5.15.0-1019.24~20.04.1.1
Ubuntu:20.04:LTS linux-bluefield 0 5.4.0-1007.10
Ubuntu:20.04:LTS linux-gcp 0 5.4.0-1005.5
Ubuntu:20.04:LTS linux-gcp-5.11 0 No fix
Ubuntu:20.04:LTS linux-gcp-5.13 0 No fix
Ubuntu:20.04:LTS linux-gcp-5.15 0 5.15.0-1006.9~20.04.1
Ubuntu:20.04:LTS linux-gcp-5.8 0 No fix
Ubuntu:20.04:LTS linux-gke 0 No fix
Ubuntu:20.04:LTS linux-gke-5.15 0 No fix
Ubuntu:20.04:LTS linux-gkeop 0 5.4.0-1008.9
Ubuntu:20.04:LTS linux-gkeop-5.15 0 5.15.0-1003.5~20.04.2
Ubuntu:20.04:LTS linux-hwe-5.11 0 No fix
Ubuntu:20.04:LTS linux-hwe-5.13 0 No fix
Ubuntu:20.04:LTS linux-hwe-5.15 0 5.15.0-33.34~20.04.1
Ubuntu:20.04:LTS linux-hwe-5.8 0 No fix
Ubuntu:20.04:LTS linux-ibm 0 5.4.0-1003.4
Ubuntu:20.04:LTS linux-ibm-5.15 0 5.15.0-1033.36~20.04.1
Ubuntu:20.04:LTS linux-intel-5.13 0 No fix
Ubuntu:20.04:LTS linux-intel-iotg-5.15 0 5.15.0-1003.5~20.04.1
Ubuntu:20.04:LTS linux-iot 0 5.4.0-1001.3
Ubuntu:20.04:LTS linux-kvm 0 5.4.0-1004.4
Ubuntu:20.04:LTS linux-lowlatency-hwe-5.15 0 5.15.0-33.34~20.04.1
Ubuntu:20.04:LTS linux-oem-5.10 0 No fix
Ubuntu:20.04:LTS linux-oem-5.13 0 No fix
Ubuntu:20.04:LTS linux-oem-5.14 0 No fix
Ubuntu:20.04:LTS linux-oem-5.6 0 No fix
Ubuntu:20.04:LTS linux-oracle 0 5.4.0-1005.5
Ubuntu:20.04:LTS linux-oracle-5.11 0 No fix
Ubuntu:20.04:LTS linux-oracle-5.13 0 No fix
Ubuntu:20.04:LTS linux-oracle-5.15 0 5.15.0-1007.9~20.04.1
Ubuntu:20.04:LTS linux-oracle-5.8 0 No fix
Ubuntu:20.04:LTS linux-raspi 0 5.4.0-1007.7
Ubuntu:20.04:LTS linux-raspi2 0 No fix
Ubuntu:20.04:LTS linux-riscv 0 No fix
Ubuntu:20.04:LTS linux-riscv-5.11 0 No fix
Ubuntu:20.04:LTS linux-riscv-5.15 0 5.15.0-1015.17~20.04.1
Ubuntu:20.04:LTS linux-riscv-5.8 0 No fix
Ubuntu:20.04:LTS linux-xilinx-zynqmp 0 5.4.0-1020.24
Ubuntu:22.04:LTS linux 0 5.13.0-19.19
Ubuntu:22.04:LTS linux-allwinner-5.19 0 No fix
Ubuntu:22.04:LTS linux-aws 0 5.13.0-1005.6
Ubuntu:22.04:LTS linux-aws-5.19 0 No fix
Ubuntu:22.04:LTS linux-aws-6.2 0 No fix
Ubuntu:22.04:LTS linux-aws-6.5 0 6.5.0-1008.8~22.04.1
Ubuntu:22.04:LTS linux-azure 0 5.13.0-1006.7
Ubuntu:22.04:LTS linux-azure-5.19 0 No fix
Ubuntu:22.04:LTS linux-azure-6.2 0 No fix
Ubuntu:22.04:LTS linux-azure-6.5 0 6.5.0-1007.7~22.04.1
Ubuntu:22.04:LTS linux-azure-fde 0 5.15.0-1019.24.1
Ubuntu:22.04:LTS linux-azure-fde-5.19 0 No fix
Ubuntu:22.04:LTS linux-azure-fde-6.2 0 No fix
Ubuntu:22.04:LTS linux-gcp 0 5.13.0-1005.6
Ubuntu:22.04:LTS linux-gcp-5.19 0 No fix
Ubuntu:22.04:LTS linux-gcp-6.2 0 No fix
Ubuntu:22.04:LTS linux-gcp-6.5 0 6.5.0-1010.10~22.04.3
Ubuntu:22.04:LTS linux-gke 0 5.15.0-1002.2
Ubuntu:22.04:LTS linux-gkeop 0 5.15.0-1001.2
Ubuntu:22.04:LTS linux-hwe-5.19 0 No fix
Ubuntu:22.04:LTS linux-hwe-6.2 0 No fix
Ubuntu:22.04:LTS linux-hwe-6.5 0 6.5.0-14.14~22.04.1
Ubuntu:22.04:LTS linux-ibm 0 5.15.0-1002.2
Ubuntu:22.04:LTS linux-intel-iotg 0 5.15.0-1004.6
Ubuntu:22.04:LTS linux-kvm 0 5.13.0-1004.4
Ubuntu:22.04:LTS linux-lowlatency 0 5.15.0-22.22
Ubuntu:22.04:LTS linux-lowlatency-hwe-5.19 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-6.2 0 No fix
Ubuntu:22.04:LTS linux-lowlatency-hwe-6.5 0 6.5.0-14.14.1~22.04.1
Ubuntu:22.04:LTS linux-nvidia 0 5.15.0-1005.5
Ubuntu:22.04:LTS linux-nvidia-6.2 0 No fix
Ubuntu:22.04:LTS linux-nvidia-6.5 0 6.5.0-1004.4
Ubuntu:22.04:LTS linux-nvidia-6.8 0 6.8.0-1008.8~22.04.1
Ubuntu:22.04:LTS linux-oem-5.17 0 No fix
Ubuntu:22.04:LTS linux-oem-6.0 0 No fix
Ubuntu:22.04:LTS linux-oem-6.1 0 No fix
Ubuntu:22.04:LTS linux-oem-6.5 0 6.5.0-1003.3
Ubuntu:22.04:LTS linux-oracle 0 5.13.0-1008.10
Ubuntu:22.04:LTS linux-oracle-6.5 0 6.5.0-1013.13~22.04.4
Ubuntu:22.04:LTS linux-raspi 0 5.13.0-1008.9
Ubuntu:22.04:LTS linux-riscv 0 No fix
Ubuntu:22.04:LTS linux-riscv-5.19 0 No fix
Ubuntu:22.04:LTS linux-riscv-6.5 0 6.5.0-17.17.1.1~22.04.1
Ubuntu:22.04:LTS linux-starfive-5.19 0 No fix
Ubuntu:22.04:LTS linux-starfive-6.2 0 No fix
Ubuntu:22.04:LTS linux-starfive-6.5 0 6.5.0-1007.8~22.04.1
Ubuntu:22.04:LTS linux-xilinx-zynqmp 0 5.15.0-1022.26
Ubuntu:24.04:LTS linux 0 6.5.0-9.9
Ubuntu:24.04:LTS linux-aws 0 6.5.0-1008.8
Ubuntu:24.04:LTS linux-azure 0 6.5.0-1007.7
Ubuntu:24.04:LTS linux-gcp 0 6.5.0-1007.7
Ubuntu:24.04:LTS linux-gke 0 6.8.0-1003.5
Ubuntu:24.04:LTS linux-gkeop 0 6.8.0-1001.3
Ubuntu:24.04:LTS linux-ibm 0 6.5.0-1009.9
Ubuntu:24.04:LTS linux-lowlatency 0 6.5.0-9.9.1
Ubuntu:24.04:LTS linux-nvidia 0 6.8.0-1007.7
Ubuntu:24.04:LTS linux-nvidia-lowlatency 0 6.8.0-1009.9.1
Ubuntu:24.04:LTS linux-oem-6.8 0 6.8.0-1003.3
Ubuntu:24.04:LTS linux-oracle 0 6.5.0-1010.10
Ubuntu:24.04:LTS linux-raspi 0 6.5.0-1005.7
Ubuntu:24.04:LTS linux-riscv 0 6.5.0-9.9.1
Ubuntu:Pro:16.04:LTS linux-hwe-edge 0 No fix
Ubuntu:Pro:18.04:LTS linux-aws-5.0 0 No fix
Ubuntu:Pro:18.04:LTS linux-aws-5.3 0 No fix
Ubuntu:Pro:18.04:LTS linux-azure 0 No fix
Ubuntu:Pro:18.04:LTS linux-azure-5.3 0 No fix
Ubuntu:Pro:18.04:LTS linux-azure-edge 0 No fix
Ubuntu:Pro:18.04:LTS linux-gcp 0 No fix
Ubuntu:Pro:18.04:LTS linux-gcp-5.3 0 No fix
Ubuntu:Pro:18.04:LTS linux-gke-4.15 0 No fix
Ubuntu:Pro:18.04:LTS linux-gke-5.4 0 No fix
Ubuntu:Pro:18.04:LTS linux-gkeop-5.4 0 No fix
Ubuntu:Pro:18.04:LTS linux-hwe 0 No fix
Ubuntu:Pro:18.04:LTS linux-hwe-edge 0 No fix
Ubuntu:Pro:18.04:LTS linux-oem 0 No fix
Ubuntu:Pro:18.04:LTS linux-oracle-5.0 0 No fix
Ubuntu:Pro:18.04:LTS linux-oracle-5.3 0 No fix
Ubuntu:Pro:20.04:LTS linux-aws-5.11 0 No fix
Ubuntu:Pro:20.04:LTS linux-aws-5.13 0 No fix
Ubuntu:Pro:20.04:LTS linux-aws-5.8 0 No fix
Ubuntu:Pro:20.04:LTS linux-azure-5.11 0 No fix
Ubuntu:Pro:20.04:LTS linux-azure-5.13 0 No fix
Ubuntu:Pro:20.04:LTS linux-azure-5.8 0 No fix
Ubuntu:Pro:20.04:LTS linux-azure-fde 0 No fix
Ubuntu:Pro:20.04:LTS linux-gcp-5.11 0 No fix
Ubuntu:Pro:20.04:LTS linux-gcp-5.13 0 No fix
Ubuntu:Pro:20.04:LTS linux-gcp-5.8 0 No fix
Ubuntu:Pro:20.04:LTS linux-gke 0 No fix
Ubuntu:Pro:20.04:LTS linux-gke-5.15 0 No fix
Ubuntu:Pro:20.04:LTS linux-hwe-5.11 0 No fix
Ubuntu:Pro:20.04:LTS linux-hwe-5.13 0 No fix
Ubuntu:Pro:20.04:LTS linux-hwe-5.8 0 No fix
Ubuntu:Pro:20.04:LTS linux-intel-5.13 0 No fix
Ubuntu:Pro:20.04:LTS linux-oem-5.10 0 No fix
Ubuntu:Pro:20.04:LTS linux-oem-5.13 0 No fix
Ubuntu:Pro:20.04:LTS linux-oem-5.14 0 No fix
Ubuntu:Pro:20.04:LTS linux-oem-5.6 0 No fix
Ubuntu:Pro:20.04:LTS linux-oracle-5.11 0 No fix
Ubuntu:Pro:20.04:LTS linux-oracle-5.13 0 No fix
Ubuntu:Pro:20.04:LTS linux-oracle-5.8 0 No fix
Ubuntu:Pro:20.04:LTS linux-raspi2 0 No fix
Ubuntu:Pro:20.04:LTS linux-riscv 0 No fix
Ubuntu:Pro:20.04:LTS linux-riscv-5.11 0 No fix
Ubuntu:Pro:20.04:LTS linux-riscv-5.8 0 No fix
Ubuntu:Pro:FIPS-updates:18.04:LTS linux-aws-fips 0 4.15.0-2000.4
Ubuntu:Pro:FIPS-updates:18.04:LTS linux-azure-fips 0 4.15.0-1002.2
Ubuntu:Pro:FIPS-updates:18.04:LTS linux-fips 0 4.15.0-1027.32
Ubuntu:Pro:FIPS-updates:18.04:LTS linux-gcp-fips 0 4.15.0-2013.14
Ubuntu:Pro:FIPS-updates:20.04:LTS linux-aws-fips 0 5.4.0-1021.21+fips2
Ubuntu:Pro:FIPS-updates:20.04:LTS linux-azure-fips 0 5.4.0-1022.22+fips1
Ubuntu:Pro:FIPS-updates:20.04:LTS linux-fips 0 5.4.0-1026.30
Ubuntu:Pro:FIPS-updates:20.04:LTS linux-gcp-fips 0 5.4.0-1021.21+fips1
Ubuntu:Pro:FIPS:16.04:LTS linux-fips 0 4.4.0-1003.3
Ubuntu:Pro:FIPS:18.04:LTS linux-aws-fips 0 4.15.0-2000.4
Ubuntu:Pro:FIPS:18.04:LTS linux-azure-fips 0 4.15.0-1002.2
Ubuntu:Pro:FIPS:18.04:LTS linux-fips 0 4.15.0-1011.12
Ubuntu:Pro:FIPS:18.04:LTS linux-gcp-fips 0 4.15.0-1001.1
Ubuntu:Pro:FIPS:20.04:LTS linux-aws-fips 0 5.4.0-1021.21+fips2
Ubuntu:Pro:FIPS:20.04:LTS linux-azure-fips 0 5.4.0-1022.22+fips1
Ubuntu:Pro:FIPS:20.04:LTS linux-fips 0 5.4.0-1007.8
Ubuntu:Pro:FIPS:20.04:LTS linux-gcp-fips 0 5.4.0-1021.21+fips1

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