Description
In the Linux kernel, the following vulnerability has been resolved:
blk-iocost: fix divide by 0 error in calc_lcoefs()
echo max of u64 to cost.model can cause divide by 0 error.
# echo 8:0 rbps=18446744073709551615 > /sys/fs/cgroup/io.cost.model
divide error: 0000 [#1] PREEMPT SMP
RIP: 0010:calc_lcoefs+0x4c/0xc0
Call Trace:
<TASK>
ioc_refresh_params+0x2b3/0x4f0
ioc_cost_model_write+0x3cb/0x4c0
? _copy_from_iter+0x6d/0x6c0
? kernfs_fop_write_iter+0xfc/0x270
cgroup_file_write+0xa0/0x200
kernfs_fop_write_iter+0x17d/0x270
vfs_write+0x414/0x620
ksys_write+0x73/0x160
__x64_sys_write+0x1e/0x30
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
calc_lcoefs() uses the input value of cost.model in DIV_ROUND_UP_ULL,
overflow would happen if bps plus IOC_PAGE_SIZE is greater than
ULLONG_MAX, it can cause divide by 0 error.
Fix the problem by setting basecost
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.4 | 5.4.235 |
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 | 6.1.20-1 | — |
| Debian 13 | linux | 6.1.20-1 | — |
| Debian 12 | linux | 6.1.20-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 22.04 LTS | linux-bluefield | 5.15.0-1019.21 | — |
| Ubuntu 24.04 LTS | linux-riscv +10 | No fix yet | — |
| Ubuntu 22.04 LTS | linux +1 | 5.15.0-75.82 | — |
| Ubuntu 22.04 LTS | linux-aws | 5.15.0-1038.43 | — |
| Ubuntu 22.04 LTS | linux-azure | 5.15.0-1040.47 | — |
| Ubuntu 22.04 LTS | linux-azure-fde | 5.15.0-1041.48.1 | — |
| Ubuntu 22.04 LTS | linux-gcp | 5.15.0-1036.44 | — |
| Ubuntu 22.04 LTS | linux-gke | 5.15.0-1036.41 | — |
| Ubuntu 22.04 LTS | linux-gkeop | 5.15.0-1022.27 | — |
| Ubuntu 22.04 LTS | linux-ibm +1 | 5.15.0-1032.35 | — |
| Ubuntu 22.04 LTS | linux-intel-iotg | 5.15.0-1033.38 | — |
| Ubuntu 22.04 LTS | linux-kvm | 5.15.0-1035.40 | — |
| Ubuntu 22.04 LTS | linux-nvidia | 5.15.0-1027.27 | — |
| Ubuntu 22.04 LTS | linux-nvidia-tegra | 5.15.0-1015.15 | — |
| Ubuntu 22.04 LTS | linux-oracle | 5.15.0-1037.43 | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 20.04 LTS | linux | 5.4.0-152.169 | — |
| Ubuntu 20.04 LTS | linux-aws | 5.4.0-1104.112 | — |
| Ubuntu 20.04 LTS | linux-aws-5.15 | 5.15.0-1038.43~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-azure | 5.4.0-1110.116 | — |
| Ubuntu 20.04 LTS | linux-azure-5.15 | 5.15.0-1040.47~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-bluefield | 5.4.0-1065.71 | — |
| Ubuntu 20.04 LTS | linux-gcp | 5.4.0-1107.116 | — |
| Ubuntu 20.04 LTS | linux-gcp-5.15 | 5.15.0-1036.44~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-hwe-5.15 +1 | 5.15.0-75.82~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-ibm | 5.4.0-1051.56 | — |
| Ubuntu 20.04 LTS | linux-intel-iotg-5.15 | 5.15.0-1033.38~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-iot | 5.4.0-1017.18 | — |
| Ubuntu 20.04 LTS | linux-kvm | 5.4.0-1093.99 | — |
| Ubuntu 20.04 LTS | linux-nvidia-tegra-5.15 | 5.15.0-1015.15~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-oracle | 5.4.0-1103.112 | — |
| Ubuntu 20.04 LTS | linux-oracle-5.15 | 5.15.0-1037.43~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-raspi | 5.4.0-1088.99 | — |
| Ubuntu 20.04 LTS | linux-riscv-5.15 | 5.15.0-1035.39~20.04.1 | — |
| Ubuntu 20.04 LTS | linux-xilinx-zynqmp | 5.4.0-1024.28 | — |
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
Show 6 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-intel-iot-realtime | 5.15.0-1033.35 | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime | 5.15.0-1040.45 | — |
| Ubuntu Pro FIPS 20.04 LTS | linux-fips +3 | No fix yet | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-aws-fips | 5.4.0-1104.112+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-azure-fips | 5.4.0-1110.116+fips1 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-fips | 5.4.0-1079.88 | — |
| Ubuntu Pro FIPS-updates 20.04 LTS | linux-gcp-fips | 5.4.0-1107.116+fips1 | — |
| Ubuntu Pro FIPS-preview 22.04 LTS | linux-fips | No fix yet | — |
| Ubuntu Pro 18.04 LTS | linux-aws-5.4 | 5.4.0-1104.112~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-azure-5.4 | 5.4.0-1110.116~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-gcp-5.4 | 5.4.0-1107.116~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-hwe-5.4 | 5.4.0-152.169~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-ibm-5.4 | 5.4.0-1051.56~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-oracle-5.4 | 5.4.0-1103.112~18.04.1 | — |
| Ubuntu Pro 18.04 LTS | linux-raspi-5.4 | 5.4.0-1088.99~18.04.1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP5 | kernel-64kb +6 | 5.14.21-150500.55.133.1 | SUSE-SU-2026:0317-1 |
| SLES 15 SP5 | kernel-default-base | 5.14.21-150500.55.133.1.150500.6.65.1 | SUSE-SU-2026:0317-1 |
| SLES 15 SP4 | kernel-64kb +6 | 5.14.21-150400.24.194.1 | SUSE-SU-2026:0617-1 |
| SLES 15 SP4 | kernel-default-base | 5.14.21-150400.24.194.1.150400.24.98.3 | SUSE-SU-2026:0617-1 |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP5 | kernel-default-base | 5.14.21-150500.55.133.1.150500.6.65.1 | SUSE-SU-2026:0317-1 |
| SLES for SAP 15 SP5 | kernel-docs +4 | 5.14.21-150500.55.133.1 | SUSE-SU-2026:0317-1 |
| SLES for SAP 15 SP4 | kernel-default-base | 5.14.21-150400.24.194.1.150400.24.98.3 | SUSE-SU-2026:0617-1 |
| SLES for SAP 15 SP4 | kernel-docs +4 | 5.14.21-150400.24.194.1 | SUSE-SU-2026:0617-1 |
| SLE Micro 5.5 | kernel-default-base | 5.14.21-150500.55.133.1.150500.6.65.1 | SUSE-SU-2026:0317-1 |
| SLE Micro 5.5 | kernel-rt +1 | 5.14.21-150500.13.118.1 | SUSE-SU-2026:0263-1 |
| SLE Micro 5.5 | kernel-source +1 | 5.14.21-150500.55.133.1 | SUSE-SU-2026:0317-1 |
| SLE Micro 5.4 | kernel-default | 5.14.21-150400.24.194.1 | SUSE-SU-2026:0617-1 |
| SLE Micro 5.4 | kernel-default-base | 5.14.21-150400.24.194.1.150400.24.98.3 | SUSE-SU-2026:0617-1 |
| SLE Micro 5.4 | kernel-rt +1 | 5.14.21-150400.15.142.1 | SUSE-SU-2026:0411-1 |
| SLE Micro 5.3 | kernel-default | 5.14.21-150400.24.194.1 | SUSE-SU-2026:0617-1 |
| SLE Micro 5.3 | kernel-default-base | 5.14.21-150400.24.194.1.150400.24.98.3 | SUSE-SU-2026:0617-1 |
| SLE Micro 5.3 | kernel-rt +1 | 5.14.21-150400.15.142.1 | SUSE-SU-2026:0411-1 |
| SLE Live Patching 15 SP5 | kernel-default | 5.14.21-150500.55.133.1 | SUSE-SU-2026:0317-1 |
| SLE Live Patching 15 SP5 | kernel-livepatch-SLE15-SP5_Update_34 | 1-150500.11.3.1 | SUSE-SU-2026:0317-1 |
| SLE Live Patching 15 SP4 | kernel-default | 5.14.21-150400.24.194.1 | SUSE-SU-2026:0617-1 |
| SLE Live Patching 15 SP4 | kernel-livepatch-SLE15-SP4_Update_48 | 1-150400.9.7.1 | SUSE-SU-2026:0617-1 |
| SLE HPC 15 SP5 | kernel-64kb +5 | 5.14.21-150500.55.133.1 | SUSE-SU-2026:0317-1 |
| SLE HPC 15 SP5 | kernel-default-base | 5.14.21-150500.55.133.1.150500.6.65.1 | SUSE-SU-2026:0317-1 |
| SLE HPC 15 SP4 | kernel-64kb +5 | 5.14.21-150400.24.194.1 | SUSE-SU-2026:0617-1 |
| SLE HPC 15 SP4 | kernel-default-base | 5.14.21-150400.24.194.1.150400.24.98.3 | SUSE-SU-2026:0617-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.1.19-30.43 | 1.0-0.amzn2023 | ALAS2023-2023-138 |
| Amazon Linux 2023 | perf +12 | 6.1.19-30.43.amzn2023 | ALAS2023-2023-138 |
Advisories 6
- WID-SEC-2025-2765 Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service BSI CERT-Bund (WID) · Nov 12, 2026
- SUSE-SU-2026:0317-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Mar 23, 2026
- SUSE-SU-2026:0617-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 26, 2026
- SUSE-SU-2026:0411-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 10, 2026
- ALAS2023-2023-138 Important: kernel security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Feb 8, 2026
- SUSE-SU-2026:0263-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://git.kernel.org/stable/c/9e8bf9f95f7a299fa9ea45b678d001806ad5e12c
- https://git.kernel.org/stable/c/6e291810fe83a384700eb24a1f714966391ed562
- https://git.kernel.org/stable/c/3538ade9d8c2ba41088e395de916f2599fadba8f
- https://git.kernel.org/stable/c/bf8eb1fd6110871e6232e8e7efe399276ef7e6f6
- https://git.kernel.org/stable/c/b96d7b4a9745fbd0c8384608ceb1f50415e862fa
- https://git.kernel.org/stable/c/984af1e66b4126cf145153661cc24c213e2ec231