Description
In the Linux kernel, the following vulnerability has been resolved:
cgroup: split cgroup_destroy_wq into 3 workqueues
A hung task can occur during [1] LTP cgroup testing when repeatedly
mounting/unmounting perf_event and net_prio controllers with
systemd.unified_cgroup_hierarchy=1. The hang manifests in
cgroup_lock_and_drain_offline() during root destruction.
Related case:
cgroup_fj_function_perf_event cgroup_fj_function.sh perf_event
cgroup_fj_function_net_prio cgroup_fj_function.sh net_prio
Call Trace:
cgroup_lock_and_drain_offline+0x14c/0x1e8
cgroup_destroy_root+0x3c/0x2c0
css_free_rwork_fn+0x248/0x338
process_one_work+0x16c/0x3b8
worker_thread+0x22c/0x3b0
kthread+0xec/0x100
ret_from_fork+0x10/0x20
Root Cause:
CPU0 CPU1
mount perf_event umount net_prio
cgroup1_get_tree cgroup_kill_sb
rebind_subsystems // root destruction enqueues
// cgroup_destroy_wq
// kill all perf_event css
// one perf_event css A is dying
// css A offline enqueues cgroup_destroy_wq
// root destruction will be executed first
css_free_rwork_fn
cgroup_destroy_root
cgroup_lock_and_drain_offline
// some perf descendants are dying
// cgroup_destroy_wq max_active = 1
// waiting for css A to die
Problem scenario:
1. CPU0 mounts perf_event (rebind_subsystems)
2. CPU1 unmounts net_prio (cgroup_kill_sb), queuing root destruction work
3. A dying perf_event CSS gets queued for offline after root destruction
4. Root destruction waits for offline completion, but offline work is
blocked behind root destruction in cgroup_destroy_wq (max_active=1)
Solution:
Split cgroup_destroy_wq into three dedicated workqueues:
cgroup_offline_wq – Handles CSS offline operations
cgroup_release_wq – Manages resource release
cgroup_free_wq – Performs final memory deallocation
This separation eliminates blocking in the CSS free path while waiting for
offline operations to complete.
[1] https://github.com/linux-test-project/ltp/blob/master/runtest/controllers
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 4.6 | 5.4.300 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 6.16.9-1 | — |
| Debian 13 | linux | 6.12.57-1 | — |
| Debian 12 | linux | 6.1.158-1 | DSA-6053-1 |
| Debian 11 | linux | 5.10.247-1 | DLA-4404-1 |
| Debian 11 | linux-6.1 | 6.1.158-1~deb11u1 | DLA-4379-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | 6.8.0-1017.21 | — |
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | 5.15.0-1084.86 | — |
| Ubuntu 25.10 | linux-azure-fde | No fix yet | — |
| Ubuntu 24.04 LTS | linux | 6.8.0-106.106 | USN-8095-1 |
| Ubuntu 24.04 LTS | linux-aws | 6.8.0-1050.53 | USN-8095-1 |
| Ubuntu 24.04 LTS | linux-azure | 6.8.0-1051.57 | USN-8125-1 |
| Ubuntu 24.04 LTS | linux-azure-fde | 6.8.0-1058.65 | — |
| Ubuntu 24.04 LTS | linux-azure-nvidia | 6.8.0-1039.42 | — |
| Ubuntu 24.04 LTS | linux-gcp | 6.8.0-1052.55 | USN-8095-1 |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1048.53 | USN-8095-1 |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1035.38 | USN-8095-1 |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1049.49 | USN-8095-1 |
| Ubuntu 24.04 LTS | linux-intel +19 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-lowlatency | 6.8.0-106.106.1 | USN-8095-1 |
| Ubuntu 24.04 LTS | linux-nvidia | 6.8.0-1049.52 | USN-8100-1 |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1049.52.1 | USN-8100-1 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1020.20 | — |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1047.48 | USN-8095-1 |
| Ubuntu 24.04 LTS | linux-raspi | 6.8.0-1050.54 | USN-8095-5 |
| Ubuntu 24.04 LTS | linux-xilinx | 6.8.0-1028.29 | USN-8261-1 |
| Ubuntu 22.04 LTS | linux +1 | 5.15.0-170.180 | USN-8033-1 |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1100.107 | USN-8033-1 |
| Ubuntu 22.04 LTS | linux-aws-6.8 | 6.8.0-1050.53~22.04.1 | USN-8095-4 |
| Ubuntu 22.04 LTS | linux-azure | 5.15.0-1109.118 | USN-8163-2 |
| Ubuntu 22.04 LTS | linux-azure-6.8 | 6.8.0-1051.57~22.04.1 | USN-8126-1 |
| Ubuntu 22.04 LTS | linux-azure-fde | 5.15.0-1109.118.1 | — |
| Ubuntu 22.04 LTS | linux-azure-fde-6.8 | 6.8.0-1058.65~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1100.109 | USN-8033-1 |
| Ubuntu 22.04 LTS | linux-gcp-6.8 | 6.8.0-1052.55~22.04.1 | USN-8095-1 |
| Ubuntu 22.04 LTS | linux-gke | 5.15.0-1096.102 | USN-8033-1 |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1083.91 | USN-8033-1 |
| Ubuntu 22.04 LTS | linux-hwe-6.8 +1 | 6.8.0-106.106~22.04.1 | USN-8095-1 |
| Ubuntu 22.04 LTS | linux-ibm | 5.15.0-1094.97 | USN-8033-1 |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1049.49~22.04.1 | USN-8095-1 |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1095.101 | USN-8033-8 |
| Ubuntu 22.04 LTS | linux-kvm | 5.15.0-1092.97 | USN-8033-5 |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.8 | 6.8.0-106.106.1~22.04.1 | USN-8095-1 |
| Ubuntu 22.04 LTS | linux-nvidia | 5.15.0-1095.96 | USN-8033-6 |
| Ubuntu 22.04 LTS | linux-nvidia-6.8 | 6.8.0-1049.52~22.04.1 | USN-8100-1 |
| Ubuntu 22.04 LTS | linux-nvidia-tegra | 5.15.0-1052.52 | USN-8034-1 |
| Ubuntu 22.04 LTS | linux-nvidia-tegra-igx | 5.15.0-1041.41 | USN-8034-2 |
| Ubuntu 22.04 LTS | linux-oracle | 5.15.0-1097.103 | USN-8033-5 |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1047.48~22.04.1 | USN-8095-1 |
| Ubuntu 22.04 LTS | linux-raspi | 5.15.0-1097.100 | USN-8141-1 |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-xilinx-zynqmp | 5.15.0-1064.68 | USN-8033-7 |
Show 16 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-raspi-realtime | 6.8.0-2040.41 | USN-8095-5 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime | 6.8.1-1045.46 | USN-8095-3 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.14 | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1092.94 | USN-8033-2 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1099.108 | USN-8033-2 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1045.46~22.04.1 | USN-8095-3 |
| Ubuntu Pro FIPS 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-aws-fips | 6.8.0-1050.53+fips1 | USN-8095-2 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-azure-fips | 6.8.0-1052.58+fips1 | USN-8165-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | 6.8.0-106.106+fips1 | USN-8095-2 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-gcp-fips | 6.8.0-1052.55+fips1 | USN-8095-2 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-aws-fips | 5.15.0-1100.107+fips1 | USN-8033-3 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-azure-fips | 5.15.0-1109.118+fips1 | USN-8163-1 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-fips | 5.15.0-170.180+fips1 | USN-8033-3 |
| Ubuntu Pro FIPS-updates 22.04 LTS | linux-gcp-fips | 5.15.0-1100.109+fips1 | USN-8033-3 |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 18.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux +10 | No fix yet | — |
| Ubuntu Pro 20.04 LTS | linux-aws-5.15 | 5.15.0-1100.107~20.04.2 | USN-8033-4 |
| Ubuntu Pro 20.04 LTS | linux-azure-5.15 | 5.15.0-1110.119~20.04.1 | USN-8243-1 |
| Ubuntu Pro 20.04 LTS | linux-gcp-5.15 | 5.15.0-1100.109~20.04.1 | USN-8033-5 |
| Ubuntu Pro 20.04 LTS | linux-hwe-5.15 | 5.15.0-170.180~20.04.3 | USN-8033-1 |
| Ubuntu Pro 20.04 LTS | linux-ibm-5.15 | 5.15.0-1094.97~20.04.1 | USN-8033-1 |
| Ubuntu Pro 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1095.101~20.04.1 | USN-8033-7 |
| Ubuntu Pro 20.04 LTS | linux-lowlatency-hwe-5.15 | 5.15.0-170.180~20.04.1 | USN-8033-1 |
| Ubuntu Pro 20.04 LTS | linux-nvidia-tegra-5.15 | 5.15.0-1052.52~20.04.2 | USN-8034-1 |
| Ubuntu Pro 20.04 LTS | linux-oracle-5.15 | 5.15.0-1097.103~20.04.1 | USN-8033-5 |
| Ubuntu Pro 20.04 LTS | linux-riscv-5.15 | 5.15.0-1095.99~20.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux +12 | No fix yet | — |
| Ubuntu Pro 16.04 LTS | linux-gcp +4 | No fix yet | — |
| Ubuntu Pro 14.04 LTS | linux-azure | No fix yet | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.12.53-69.119 +1 | 1:1.0-0.amzn2023 | ALAS2023-2025-1254, ALAS2023-2025-1223 |
| Amazon Linux 2023 | perf +14 | 1:6.1.155-176.282.amzn2023 | ALAS2023-2025-1223 |
| Amazon Linux 2023 | perf6.12 +14 | 1:6.12.53-69.119.amzn2023 | ALAS2023-2025-1254 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | kernel | 6.6.112.1-1 | — |
| Azure Linux 2 (CBL-Mariner) | kernel | 5.15.200.1-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-105.51.5.el10uek | ELSA-2025-25754 |
| Oracle Linux 8 | bpftool +18 | 5.15.0-315.196.5.1.el9uek | ELSA-2025-28048 |
| Oracle Linux 7 | kernel-uek +6 | 5.4.17-2136.350.3.1.el8uek | ELSA-2025-28049 |
| Oracle Linux 7 | kernel-uek-tools | 5.4.17-2136.350.3.1.el7uek | ELSA-2025-28049 |
Advisories 37
- WID-SEC-2025-2194 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- SSA-457936 SSA-457936: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1.7 Siemens ProductCERT · Nov 10, 2026
- USN-8243-1 linux-azure-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8100-1 linux-nvidia, linux-nvidia-6.8, linux-nvidia-lowlatency vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8163-1 linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8141-1 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8165-1 linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8163-2 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8034-2 linux-nvidia-tegra-igx vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8033-1 linux, linux-aws, linux-gcp, linux-gke, linux-gkeop, linux-hwe-5.15, linux-ibm, linux-ibm-5.15, linux-lowlatency, linux-lowlatency-hwe-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8034-1 linux-nvidia-tegra, linux-nvidia-tegra-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8033-4 linux-aws-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8033-8 linux-intel-iotg vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8033-3 linux-aws-fips, linux-fips, linux-gcp-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8033-7 linux-intel-iotg-5.15, linux-xilinx-zynqmp vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8033-5 linux-gcp-5.15, linux-kvm, linux-oracle, linux-oracle-5.15 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8033-2 linux-intel-iot-realtime, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8033-6 linux-nvidia vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8095-1 linux, linux-aws, linux-gcp, linux-gcp-6.8, linux-gke, linux-gkeop, linux-hwe-6.8, linux-ibm, linux-ibm-6.8, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-oracle, linux-oracle-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8095-2 linux-fips, linux-aws-fips, linux-gcp-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8126-1 linux-azure-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8095-5 linux-raspi, linux-raspi-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8125-1 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8095-4 linux-aws-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- USN-8095-3 linux-realtime, linux-realtime-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 3, 2026
- ICSA-26-295-11 Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP CISA ICS & IT advisories · Oct 22, 2026
- SSA-019113 SSA-019113: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1.6 Siemens ProductCERT · Oct 13, 2026
- USN-8261-1 linux-xilinx vulnerabilities Ubuntu Security Notices (USN) · Sep 7, 2026
- ICSA-26-209-04 Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP CISA ICS & IT advisories · Jul 28, 2026
- DLA-4404-1 linux - security update Debian Security (DSA / DLA) · Dec 12, 2025
- ELSA-2025-28048 Important: Unbreakable Enterprise kernel security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Dec 12, 2025
- ELSA-2025-28049 Important: Unbreakable Enterprise kernel security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Dec 12, 2025
- DLA-4379-1 linux-6.1 - security update Debian Security (DSA / DLA) · Nov 25, 2025
- DSA-6053-1 linux - security update Debian Security (DSA / DLA) · Nov 11, 2025
- ELSA-2025-25754 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Nov 9, 2025
- ALAS2023-2025-1254 Important: kernel6.12 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Oct 27, 2025
- ALAS2023-2025-1223 Important: kernel security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Oct 14, 2025
References
- https://git.kernel.org/stable/c/cabadd7fd15f97090f752fd22dd7f876a0dc3dc4
- https://git.kernel.org/stable/c/a0c896bda7077aa5005473e2c5b3c27173313b4c
- https://git.kernel.org/stable/c/f2795d1b92506e3adf52a298f7181032a1525e04
- https://git.kernel.org/stable/c/993049c9b1355c78918344a6403427d53f9ee700
- https://git.kernel.org/stable/c/4a1e3ec28e8062cd9f339aa6a942df9c5bcb6811
- https://git.kernel.org/stable/c/ded4d207a3209a834b6831ceec7f39b934c74802
- https://git.kernel.org/stable/c/05e0b03447cf215ec384210441b34b7a3b16e8b0
- https://git.kernel.org/stable/c/79f919a89c9d06816dbdbbd168fa41d27411a7f9