Skip to content
Fencer Vulns
high 7.8

CVE-2024-49866 json

tracing/timerlat: Fix a race during cpuhp processing

published 2024-10-21 2 y ago modified 2026-08-05 3 mo ago also EUVD-2024-43822

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

tracing/timerlat: Fix a race during cpuhp processing

There is another found exception that the "timerlat/1" thread was scheduled on CPU0, and lead to timer corruption finally:

``` ODEBUG: init active (active state 0) object: ffff888237c2e108 object type: hrtimer hint: timerlat_irq+0x0/0x220 WARNING: CPU: 0 PID: 426 at lib/debugobjects.c:518 debug_print_object+0x7d/0xb0 Modules linked in: CPU: 0 UID: 0 PID: 426 Comm: timerlat/1 Not tainted 6.11.0-rc7+ #45 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:debug_print_object+0x7d/0xb0 ... Call Trace: <TASK> ? __warn+0x7c/0x110 ? debug_print_object+0x7d/0xb0 ? report_bug+0xf1/0x1d0 ? prb_read_valid+0x17/0x20 ? handle_bug+0x3f/0x70 ? exc_invalid_op+0x13/0x60 ? asm_exc_invalid_op+0x16/0x20 ? debug_print_object+0x7d/0xb0 ? debug_print_object+0x7d/0xb0 ? __pfx_timerlat_irq+0x10/0x10 __debug_object_init+0x110/0x150 hrtimer_init+0x1d/0x60 timerlat_main+0xab/0x2d0 ? __pfx_timerlat_main+0x10/0x10 kthread+0xb7/0xe0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x2d/0x40 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> ```

After tracing the scheduling event, it was discovered that the migration of the "timerlat/1" thread was performed during thread creation. Further analysis confirmed that it is because the CPU online processing for osnoise is implemented through workers, which is asynchronous with the offline processing. When the worker was scheduled to create a thread, the CPU may has already been removed from the cpu_online_mask during the offline process, resulting in the inability to select the right CPU:

T1 | T2 [CPUHP_ONLINE] | cpu_device_down() osnoise_hotplug_workfn() | | cpus_write_lock() | takedown_cpu(1) | cpus_write_unlock() [CPUHP_OFFLINE] | cpus_read_lock() | start_kthread(1) | cpus_read_unlock() |

To fix this, skip online processing if the CPU is already offline.

Patch / fix

  • Linux Linux 5.15.168, 6.1.113, 6.6.55, 6.10.14, 6.11.3, 6.12
  • linux Debian 12 6.1.115-1
  • linux Debian 14, Debian 13 6.11.4-1

debian advisories DEBIAN-CVE-2024-49866

  • linux Ubuntu 22.04 LTS 5.15.0-127.137
  • linux Ubuntu 24.04 LTS 6.8.0-54.56
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1073.79
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1023.25
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1072.80
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1024.26
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1070.76
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1019.23

ubuntu advisories UBUNTU-CVE-2024-49866

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-source Linux Micro 6.1, Linux Micro 6.0 6.4.0-24.1
  • kernel-default Linux Micro 6.1, Linux Micro 6.0 6.4.0-24.1
  • kernel-kvmsmall Linux Micro 6.1, Linux Micro 6.0 6.4.0-24.1
  • kernel-default-base Linux Micro 6.1, Linux Micro 6.0 6.4.0-24.1.21.4
  • kernel-livepatch-MICRO-6-0_Update_4 Linux Micro 6.1, Linux Micro 6.0 1-1.2
  • kernel-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-22.1
  • kernel-source-rt Linux Micro 6.1, Linux Micro 6.0 6.4.0-22.1
  • kernel-livepatch-MICRO-6-0-RT_Update_4 Linux Micro 6.1, Linux Micro 6.0 1-1.1

suse advisories SUSE-SU-2025:20164-1SUSE-SU-2025:20247-1SUSE-SU-2025:20163-1SUSE-SU-2025:20246-1SUSE-SU-2024:4387-1SUSE-SU-2024:4364-1

  • kernel-source-longterm openSUSE Tumbleweed 6.12.11-1.1
  • kernel-source openSUSE Tumbleweed 6.11.8-1.1

opensuse advisories openSUSE-SU-2025:14705-1openSUSE-SU-2024:14500-1

  • kernel CBL-Mariner 2.0 5.15.173.1-1

azure linux advisories AZL-53343

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-49866 updated cvss 4.1

kernel: tracing/timerlat: Fix a race during cpuhp processing

  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 4.7 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Weakness
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.