Description
In the Linux kernel, the following vulnerability has been resolved:
flex_proportions: make fprop_new_period() hardirq safe
Bernd has reported a lockdep splat from flexible proportions code that is
essentially complaining about the following race:
<timer fires>
run_timer_softirq - we are in softirq context
call_timer_fn
writeout_period
fprop_new_period
write_seqcount_begin(&p->sequence);
<hardirq is raised>
...
blk_mq_end_request()
blk_update_request()
ext4_end_bio()
folio_end_writeback()
__wb_writeout_add()
__fprop_add_percpu_max()
if (unlikely(max_frac < FPROP_FRAC_BASE)) {
fprop_fraction_percpu()
seq = read_seqcount_begin(&p->sequence);
- sees odd sequence so loops indefinitely
Note that a deadlock like this is only possible if the bdi has configured
maximum fraction of writeout throughput which is very rare in general but
frequent for example for FUSE bdis. To fix this problem we have to make
sure write section of the sequence counter is irqsafe.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 6.0 | 6.1.162 |
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 | 6.18.9-1 | — |
| Debian 13 | linux | 6.12.69-1 | — |
| Debian 12 | linux | 6.1.162-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | 6.8.0-1022.26 | — |
| Ubuntu 25.10 | linux +8 | No fix yet | — |
| Ubuntu 24.04 LTS | linux | 6.8.0-117.117 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-aws | 6.8.0-1055.58 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-azure | 6.8.0-1056.62 | USN-8278-2 |
| Ubuntu 24.04 LTS | linux-azure-6.17 | 6.17.0-1021.21~24.04.1 | USN-8604-1 |
| Ubuntu 24.04 LTS | linux-azure-fde | 6.8.0-1058.65 | — |
| Ubuntu 24.04 LTS | linux-azure-fde-6.17 | 6.17.0-1018.18~24.04.1 | USN-8605-1 |
| Ubuntu 24.04 LTS | linux-azure-nvidia | 6.8.0-1039.42 | — |
| Ubuntu 24.04 LTS | linux-gcp | 6.8.0-1058.61 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-gcp-6.17 | 6.17.0-1021.24~24.04.1 | USN-8570-1 |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1054.60 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1041.44 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-hwe-6.17 | 6.17.0-41.41~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1055.56 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-lowlatency | 6.8.0-117.117.1 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-nvidia | 6.8.0-1054.57 | USN-8289-1 |
| Ubuntu 24.04 LTS | linux-nvidia-6.17 | 6.17.0-1031.31 | USN-8669-1 |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1054.57.1 | USN-8289-1 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1024.24 | USN-8296-2 |
| Ubuntu 24.04 LTS | linux-oem-6.17 | 6.17.0-1030.30 | USN-8594-1 |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1054.55 | — |
| Ubuntu 24.04 LTS | linux-oracle-6.17 | 6.17.0-1019.19~24.04.3 | USN-8570-2 |
| Ubuntu 24.04 LTS | linux-raspi | 6.8.0-1056.60 | USN-8278-1 |
| Ubuntu 24.04 LTS | linux-riscv +20 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-xilinx | 6.8.0-1032.33 | USN-8499-1 |
| Ubuntu 22.04 LTS | linux-aws-6.8 | 6.8.0-1057.60~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-azure-6.8 | 6.8.0-1059.65~22.04.1 | USN-8440-1 |
| Ubuntu 22.04 LTS | linux-azure-fde-6.8 | 6.8.0-1058.65~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-gcp-6.8 | 6.8.0-1060.63~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-hwe-6.8 | 6.8.0-124.124~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1055.56~22.04.1 | USN-8278-1 |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.8 | 6.8.0-117.117.1~22.04.1 | USN-8278-1 |
| Ubuntu 22.04 LTS | linux-nvidia-6.8 | 6.8.0-1054.57~22.04.1 | USN-8289-2 |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1054.55~22.04.1 | — |
| Ubuntu 22.04 LTS | linux-riscv +32 | No fix yet | — |
| Ubuntu 22.04 LTS | linux-riscv-6.8 | 6.8.0-117.117~22.04.1 | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| 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 | 6.8.0-2045.46 | USN-8278-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime | 6.8.1-1051.52 | USN-8278-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.14 | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.17 | 6.17.0-1018.20~24.04.1 | USN-8570-1 |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1051.52~22.04.1 | USN-8278-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-aws-fips | 6.8.0-1055.58+fips1 | USN-8278-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-azure-fips | 6.8.0-1059.65+fips1 | USN-8393-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | 6.8.0-116.116+fips1 | USN-8296-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-gcp-fips | 6.8.0-1058.61+fips1 | USN-8278-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 10 | rv +76 | 6.12.0-211.37.1.el10_2 | RHSA-2026:42919 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 10 | rv +74 | 6.12.0-211.37.1.el10_2 | ALSA-2026:42919 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 10 | kernel | 6.12.0-211.37.1.el10_2 | RLSA-2026:42919 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | kernel-64kb +7 | 6.4.0-150700.53.55.1 | SUSE-SU-2026:2238-1 |
| SLES 15 SP7 | kernel-default-base | 6.4.0-150700.53.55.1.150700.17.33.1 | SUSE-SU-2026:2238-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLE Micro 6.2 | kernel-syms +1 | 6.12.0-160000.33.1 | SUSE-SU-2026:21834-1 |
| SLE Live Patching 15 SP7 | kernel-default | 6.4.0-150700.53.55.1 | SUSE-SU-2026:2238-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7_Update_15 | 1-150700.15.3.1 | SUSE-SU-2026:2238-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.12.73-95.123 +1 | 1:1.0-0.amzn2023 | ALAS2023-2026-1487, ALAS2023-2026-1468 |
| Amazon Linux 2023 | perf +14 | 1:6.1.163-186.299.amzn2023 | ALAS2023-2026-1468 |
| Amazon Linux 2023 | perf6.12 +14 | 1:6.12.73-95.123.amzn2023 | ALAS2023-2026-1487 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | kernel | 6.6.126.1-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 10 | rv +29 | 6.12.0-211.37.1.el10_2 | ELSA-2026-42919 |
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-200.74.27.el10uek | ELSA-2026-50372, ELSA-2026-50232, ELSA-2026-50160 |
Advisories 27
- WID-SEC-2026-0421 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- USN-8604-1 linux-azure-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 7, 2026
- USN-8440-1 linux-azure-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 7, 2026
- USN-8499-1 linux-xilinx vulnerabilities Ubuntu Security Notices (USN) · Nov 7, 2026
- USN-8393-1 linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 7, 2026
- USN-8669-1 linux-nvidia-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8570-1 linux-gcp-6.17, linux-realtime-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8570-2 linux-oracle-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8594-1 linux-oem-6.17 vulnerabilities Ubuntu Security Notices (USN) · Nov 6, 2026
- USN-8278-1 linux, linux-aws, linux-aws-fips, linux-gcp, linux-gcp-fips, linux-gke, linux-gkeop, linux-ibm, linux-ibm-6.8, linux-lowlatency, linux-lowlatency-hwe-6.8, linux-raspi, linux-raspi-realtime, linux-realtime, linux-realtime-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 5, 2026
- USN-8289-1 linux-nvidia, linux-nvidia-lowlatency vulnerabilities Ubuntu Security Notices (USN) · Nov 5, 2026
- USN-8289-2 linux-nvidia-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 5, 2026
- USN-8278-2 linux-azure vulnerabilities Ubuntu Security Notices (USN) · Nov 5, 2026
- USN-8296-1 linux-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- USN-8296-2 linux-nvidia-tegra vulnerabilities Ubuntu Security Notices (USN) · Nov 4, 2026
- ALSA-2026:42919 Important: kernel security, bug fix, and enhancement update AlmaLinux Security Advisories · Oct 29, 2026
- USN-8605-1 linux-azure-fde-6.17 vulnerabilities Ubuntu Security Notices (USN) · Oct 17, 2026
- RHSA-2026:42919 Red Hat Security Advisory: kernel security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Oct 15, 2026
- RLSA-2026:42919 Important: kernel security, bug fix, and enhancement update Rocky Linux Security Advisories · Jul 23, 2026
- ELSA-2026-42919 Important: kernel security, bug fix, and enhancement update (Oracle Linux 10) Oracle Linux Security Advisories (ELSA) · Jul 22, 2026
- SUSE-SU-2026:21834-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Jul 9, 2026
- ELSA-2026-50372 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Jul 2, 2026
- SUSE-SU-2026:2238-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Jul 1, 2026
- ALAS2023-2026-1487 Important: kernel6.12 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · May 9, 2026
- ELSA-2026-50232 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Apr 15, 2026
- ALAS2023-2026-1468 Important: kernel security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Mar 26, 2026
- ELSA-2026-50160 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Mar 20, 2026
References
- https://git.kernel.org/stable/c/0acc9ba7a1b5ba4d998c5753e709be904e179b75
- https://git.kernel.org/stable/c/884b2590ffcc7222cbbd6298051f4c243cc36f5d
- https://git.kernel.org/stable/c/78ede9ebd679dadf480dce6f7b798e3603f88348
- https://git.kernel.org/stable/c/b91a84299d72ae0e05551e851e47cd3008bd025b
- https://git.kernel.org/stable/c/dd9e2f5b38f1fdd49b1ab6d3a85f81c14369eacc